[tex]|\Omega|=_{12}C_3=\dfrac{12!}{3!9!}=\dfrac{10\cdot11\cdot12}{2\cdot3}=220\\|A|=4\cdot3\cdot5=60\\\\P(A)=\dfrac{60}{220}=\dfrac{3}{11}\approx0,273[/tex]
Answer:
0.273
Step-by-step explanation:
Total number of balls is 4+3+5 = 12
There are 6 ways to draw 3 different colors (WBR, WRB, BWR, BRW, RWB, RBW) each with a chance of 4/12 · 3/11 · 5/10 = 1/22
So the total chance is 6 · 1/22 = 6/22 = 3/11 ≈ 0.273
Please help! Find the equation of the line (graph provided in attached picture) Use exact numbers. y =_ x+_ ( _ represent blanks in the equation)
Answer:
[tex] y = \frac{3}{4}x - 2 [/tex]
Step-by-step explanation:
Equation of a line is given as [tex] y = mx + b [/tex]
Where,
m = slope of the line = [tex] \frac{y_2 - y_1}{x_2 - x_1} [/tex]
b = y-intercept, which is the value at the point where the line intercepts the y-axis. At this point, x = 0.
Let's find m and b to derive the equation for the line.
[tex] m = \frac{y_2 - y_1}{x_2 - x_1} [/tex]
Use the coordinate pair of any two points on the line. Let's use the following,
[tex] (0, -2) = (x_1, y_1) [/tex] => on the line, when x = 0, y = -2
[tex] (4, 1) = (x_2, y_2) [/tex] => on the line, when x = 4, y = 1
Plug in the values and solve for m
[tex] m = \frac{1 - (-2)}{4 - 0} [/tex]
[tex] m = \frac{1 + 2}{4} [/tex]
[tex] m = \frac{3}{4} [/tex]
b = -2 (the line intercepts the y-axis at this point)
Our equation would be =>
[tex] y = mx + b [/tex]
[tex] y = \frac{3}{4}x + (-2) [/tex]
[tex] y = \frac{3}{4}x - 2 [/tex]
List the sides of ΔRST in ascending order (shortest to longest). m∠R=2x+11°, m∠S=3x+23°, and m∠T=x+42°
Answer:
ST, RS, RT
Step-by-step explanation:
Angles of a triangle add up to 180°.
2x + 11° + 3x + 23° + x + 42° = 180°
6x + 76° = 180°
x = 17⅓
m∠R = 2x+11° = 45⅔°
m∠S = 3x+23° = 75°
m∠T = x+42° = 59⅓°
The shortest side is opposite the smallest angle, and the longest side is opposite the largest angle.
ST, RS, RT
solve the equation: 14<2x−1≤20
Answer:
7.5 < x≤10.5
Step-by-step explanation:
14<2x−1≤20
Add 1 to all sides
14+1<2x−1+1≤20+1
15<2x≤21
Divide each side by 2
15/2 <2x/2 ≤21/2
7.5 < x≤10.5
Steps to solve:
14 < 2x - 1 <= 20
~Add 1 to everything
15 < 2x <= 21
~Divide 2 to everything
7.5 < x <= 10.5
Best of Luck!
These two triangles are congruent by the Hypotenuse-Leg Theorem.
Answer:
[tex] y = - 2 [/tex]
Step-by-step explanation:
Given that the 2 triangles are congruent based on the Hypotenuse-leg theorem, this implies that:
[tex] x - y = x + 2 [/tex] , and [tex] 2x - y = 4x + 2y [/tex]
Using the expression, [tex] x - y = x + 2 [/tex], solve for y:
[tex] x - y - x = x + 2 - x [/tex]
[tex] - y = 2 [/tex]
[tex] y = - 2 [/tex]
This??? What is wrong with it?
Answer:
15.8 sq. in. of paper will be required.
Step-by-step explanation:
The problem is that a drinking cup does not have a cover, so only the lateral surface area counts.
I.e. We need only the first term.
A = pi r l = pi * 1.5 * sqrt(3^2+1.5^2)
= 15.81 sq. in.
Eliminate the parameter for the following set of parametric equations: x= t + 6 y= 3t – 1
Answer:
Solution : Option A
Step-by-step explanation:
What we want to do here is eliminate the parameter t. In order to do that, we can isolate t in our first equation x = t + 6 ----- ( 1 ) and then plug that value for t in the second equation y = 3t - 1. Our solution will be an equation that is not present with t.
( 1 ) x = t + 6, t = x - 6
( 2 ) y = 3( x - 6 ) - 1 ( Distribute the " 3 " in 3( x - 6 ) )
y = 3x - 18 - 1 ( Combine like terms )
y = 3x - 19
As you can see our result will be option a, y = 3x - 19.
602/100 into a decimal describe plz
Answer:
6.02
six point zero two
Step-by-step explanation:
Answer:
602 / 100= 6,02
Step-by-step explanation:
602 to divide 100 = 6,02
For the following graph, state the polar coordinate with a positive r and positive q (in radians). Explain your steps as to how you determined the coordinate (in your own words). I'm looking for answers that involve π, not degrees for your angles. State the polar coordinate with (r, -q). Explain how you found the new angle. State the polar coordinate with (-r, q). Explain how you found the new angle. State the polar coordinate with (-r, -q). Explain how you found the new angle.
the graph has 12 segments so angle enclosed by each segment is [tex] {2\pi\over 12}=\frac{\pi}6[/tex]
anti-clockwise is taken as positive, so if you want positive q, you need to rotate 8 segments [tex] q=8\frac,{\pi}6=\frac{4\pi}3 [/tex] , and and 8 circles or units so r=8
and for a negative angle, you need to rotate clockwise
Which is 4 segments from the horizontal line. so [tex]q=-\frac{2\pi}3[/tex] and r will be same, 8 units.
[not sure about -r so I won't include it in answer]
Answer:
Points : ( 8, - 2π/3 ), ( - 8, π/3 ), ( - 8, - 5π/3 )
Step-by-step explanation:
For the first two cases, ( r, θ ) r would be > 0, where r is the directed distance from the pole, and theta is the directed angle from the positive x - axis.
So when r is positive, we can tell that this point is 8 units from the pole, so r is going to be 8 in either case,
( 8, 240° ) - because r is positive, theta would have to be an angle with which it's terminal side passes through this point. As you can see that would be 2 / 3rd of 90 degrees more than a 180 degree angle,or 60 + 180 = 240 degrees.
( 8, - 120° ) - now theta will be the negative side of 360 - 240, or in other words - 120
Now let's consider the second two cases, where r is < 0. Of course the point will still be 8 units from the pole. Again for r < 0 the point will lay on the ray pointing in the opposite direction of the terminal side of theta.
( - 8, 60° ) - theta will now be 2 / 3rd of 90 degrees, or 60 degrees, for - r. Respectively the remaining degrees will be negative, 360 - 60 = 300, - 300. Thus our second point for - r will be ( - 8, - 300° )
_________________________________
So we have the points ( 8, 240° ), ( 8, - 120° ), ( - 8, 60° ), and ( - 8, - 300° ). However we only want 3 cases, so we have points ( 8, - 120° ), ( - 8, 60° ), and ( - 8, - 300° ). Let's convert the degrees into radians,
Points : ( 8, - 2π/3 ), ( - 8, π/3 ), ( - 8, - 5π/3 )
A researcher surveys middle-school students on their study habits. She finds that in a random sample of 28 middle-school students, the mean amount of time that they spend working on the computer each night is 2.4 hours with a standard deviation of 0.92 hours. She uses the sample statistics to compute a 95% confidence interval for the population mean - the the mean amount of time that all middle-school students spend working on the computer each night. What is the margin of error for this confidence interval
Answer:
The margin of error is [tex]E = 1.96 * \frac{ 0.92}{\sqrt{28 } }[/tex]
Step-by-step explanation:
From the question we are told that
The sample size is [tex]n = 28[/tex]
The sample mean is [tex]\= x = 2.4 \ hr[/tex]
The standard deviation is [tex]\sigma = 0.92 \ hr[/tex]
Given that the confidence level is 95% the the level of significance can be evaluated as
[tex]\alpha = 100 -95[/tex]
[tex]\alpha = 5 \%[/tex]
[tex]\alpha = 0.05[/tex]
Next we obtain the critical value of [tex]\frac{\alpha }{2}[/tex] from the normal distribution table,the value is [tex]Z_{\frac{\alpha }{2} } = Z_{\frac{0.05}{2} } = 1.96[/tex]
Generally the margin of error is mathematically represented as
[tex]E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }[/tex]
substituting values
[tex]E = 1.96 * \frac{ 0.92}{\sqrt{28 } }[/tex]
[tex]E = 0.3408[/tex]
Why is 12 * 10-8 is NOT a correct representation of scientific notation?
Answer:
see below
Step-by-step explanation:
Scientific notation is a * 10 ^b
a must be a number between 1 ( including 1 ) and less than 10
12 is greater than 10 so it is not scientific notation
Evaluate the expression 8p6
Answer:
Evaluate 8P6 P 6 8 using the formula nPr=n!(n−r)! P r n = n ! ( n - r ) ! . 8!(8−6)! 8 ! ( 8 - 6 ) ! Subtract 6 6 from 8 8 . 8!(2)! 8 ! ( 2 ) ! Simplify 8!(2)! 8 !
Step-by-step explanation:
evaluate" usually means to put a value in for the variable, but you don't give us a value for p. also, it is unclear if you ...
The value of the expression [tex]^8P_6[/tex] is 20160.
What is permutation?A permutation of a set in mathematics is, broadly speaking, the rearrangement of its elements if the set already has an ordered structure into a sequence or linear order.
The value of the expression is calculated as:-
[tex]^8P_6=\dfrac{8!}{8!-6!}=\dfrac{8!}{2!}[/tex]
[tex]^8P_6 =\dfrac{8\times 7\times 6\times 5\times 4\times 3\times 2}{2}[/tex]
[tex]^8P_6[/tex] = 20160
Hence, the value is 20160.
To know more about permutations follow
https://brainly.com/question/4658834
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Please answer this correctly without making mistakes
Answer:
17/16 OR [tex]1\frac{1}{16}[/tex] minutes
Step-by-step explanation:
Since Jayla spent 1/16 of a minute AND one whole minute watching a millipede crawl, we'd need to first add the two numbers.
Since the given minute is out of 16, we can convert the one minute to 16/16. This means we can add the other 1/16 of a minute.
This leaves us with Jayla watching the millipede for 17/16 OR [tex]1\frac{1}{16}[/tex] minutes.
Hope this helps!! <3 :)
Find the first six partial sums S1, S2, S3, S4, S5, S6 of the sequence whose nth term is given. 1 2 , 1 22 , 1 23 , 1 24 , . .
Answer:
the first partial sum [tex]\mathbf{S_1= \dfrac{1}{2}}[/tex]
the second partial sum [tex]\mathbf{S_2= \dfrac{3}{4} }[/tex]
the third partial sum [tex]\mathbf{S_3= \dfrac{7}{8}}[/tex]
the fourth partial sum [tex]\mathbf{S_4= \dfrac{15}{16}}[/tex]
the fifth partial sum [tex]\mathbf{S_5= \dfrac{31}{32}}[/tex]
the sixth partial sum [tex]\mathbf{S_6= \dfrac{63}{64}}[/tex]
Step-by-step explanation:
The term of the sequence are given as : [tex]\dfrac{1}{2}[/tex], [tex]\dfrac{1}{2^2}[/tex], [tex]\dfrac{1}{2^3}[/tex], [tex]\dfrac{1}{2^4 }[/tex] , . . .
The nth term for this sequence is , [tex]\mathtt{a_n =( \dfrac{1}{2})^n}[/tex]
The nth partial sum of the sequence for [tex]\mathtt{a_1,a_2,a_3.... a_n}[/tex] is [tex]\mathtt{S_n}[/tex]
where;
[tex]\mathtt{S_n = a_1 +a_2+a_3+ ...+a_n}[/tex]
The first partial sum is: [tex]\mathtt{S_1= a_1}[/tex]
[tex]\mathtt{S_1= (\dfrac{1}{2})^1}[/tex]
[tex]\mathbf{S_1= \dfrac{1}{2}}[/tex]
Therefore, the first partial sum [tex]\mathbf{S_1= \dfrac{1}{2}}[/tex]
The second partial sum is: [tex]\mathtt{S_2= a_1+a_2}[/tex]
[tex]\mathtt{S_2= (\dfrac{1}{2})^1 + (\dfrac{1}{2})^2}[/tex]
[tex]\mathtt{S_2= \dfrac{1}{2} + \dfrac{1}{4}}[/tex]
[tex]\mathtt{S_2= \dfrac{2+1}{4} }[/tex]
[tex]\mathbf{S_2= \dfrac{3}{4} }[/tex]
Therefore, the second partial sum [tex]\mathbf{S_2= \dfrac{3}{4} }[/tex]
The third partial sum is : [tex]\mathtt{S_3= a_1+a_2+a_3}[/tex]
[tex]\mathtt{S_3= (\dfrac{1}{2})^1 + (\dfrac{1}{2})^2+(\dfrac{1}{2})^3 }[/tex]
[tex]\mathtt{S_3= \dfrac{1}{2} + \dfrac{1}{4}+\dfrac{1}{8}}[/tex]
[tex]\mathtt{S_3= \dfrac{4+2+1}{8}}[/tex]
[tex]\mathbf{S_3= \dfrac{7}{8}}[/tex]
Therefore, the third partial sum [tex]\mathbf{S_3= \dfrac{7}{8}}[/tex]
The fourth partial sum : [tex]\mathtt{S_4= a_1+a_2+a_3+a_4}[/tex]
[tex]\mathtt{S_4= (\dfrac{1}{2})^1 + (\dfrac{1}{2})^2+(\dfrac{1}{2})^3+(\dfrac{1}{2})^4 }[/tex]
[tex]\mathtt{S_4= \dfrac{1}{2} + \dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}}[/tex]
[tex]\mathtt{S_4= \dfrac{8+4+2+1}{16}}[/tex]
[tex]\mathbf{S_4= \dfrac{15}{16}}[/tex]
Therefore, the fourth partial sum [tex]\mathbf{S_4= \dfrac{15}{16}}[/tex]
The fifth partial sum : [tex]\mathtt{S_5= a_1+a_2+a_3+a_4+a_5}[/tex]
[tex]\mathtt{S_5= (\dfrac{1}{2})^1 + (\dfrac{1}{2})^2+(\dfrac{1}{2})^3+(\dfrac{1}{2})^4 +(\dfrac{1}{2})^5 }[/tex]
[tex]\mathtt{S_5= \dfrac{1}{2} + \dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}}[/tex]
[tex]\mathtt{S_5= \dfrac{16+8+4+2+1}{32}}[/tex]
[tex]\mathbf{S_5= \dfrac{31}{32}}[/tex]
Therefore, the fifth partial sum [tex]\mathbf{S_5= \dfrac{31}{32}}[/tex]
The sixth partial sum: [tex]\mathtt{S_5= a_1+a_2+a_3+a_4+a_5+a_6}[/tex]
[tex]\mathtt{S_6= (\dfrac{1}{2})^1 + (\dfrac{1}{2})^2+(\dfrac{1}{2})^3+(\dfrac{1}{2})^4 +(\dfrac{1}{2})^5 +(\dfrac{1}{2})^6 }[/tex]
[tex]\mathtt{S_6= \dfrac{1}{2} + \dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64} }[/tex]
[tex]\mathtt{S_6= \dfrac{32+16+8+4+2+1}{64}}[/tex]
[tex]\mathbf{S_6= \dfrac{63}{64}}[/tex]
Therefore, the sixth partial sum [tex]\mathbf{S_6= \dfrac{63}{64}}[/tex]
Please help. I’ll mark you as brainliest if correct!
Answer:
x and y can have many values
Step-by-step explanation:
-24x - 12y = -16
Then: 24x + 12y = 16
We know: 6x + 3y = 4
X and Y can have a lot of valoues.
6x + 3y = 4
3 ( 2x + y) = 4
2x + y= 4/3
2x+y= 1.333...
99 litres of gasoline oil is poured into a cylindrical drum of 60cm in diameter. How deep is the oil in the drum?
Answer:
35 cm
Step-by-step explanation:
The volume of a cylinder is given by ...
V = πr²h
We want to find h for the given volume and diameter. First, we must convert the given values to compatible units.
1 L = 1000 cm³, so 99 L = 99,000 cm³
60 cm diameter = 2 × 30 cm radius
So, we have ...
99,000 cm³ = π(30 cm)²h
99,000/(900π) cm = h ≈ 35.01 cm
The oil is 35 cm deep in the drum.
BRAINLIST AND A THANK YOU AND 5 stars WILL BE REWARDED PLS ANSER
Answer:
The first picture's answer would be (6, 21)
Step-by-step explanation:
You have to find the points on the 8th and the 9th day, and then you would add them together, and then divide by two finding the average, which would be 24 and 18, so when added, you get 42, divided by 2 you get 21. You look on the graph for the point with 21, and you find it is on 6.
Claire has to go to the movie theater the movie starts at 4:15 pm it is a 25min walk to the theater from her home what time dose the have to leave the house to get there on time
Answer:
claire has to leave at 3:50 from her house.
Answer:
She needs to leave by 3:50 to get there on time.
Step-by-step explanation:
4:15 - 0:25 = 3:50.
you pick a card at random from an ordinary deck of 52 cards. If the card is an ace, you get 9 points; if not, you lose a point
Answer: a = 9, b = 48, c = -1
Step-by-step explanation:
"a" represents the points you receive if an Ace is picked. It is given that you get 9 points ----> a = 9
"b" represents the number of cards that are Not an Ace. 4 cards in the deck are Aces so 52 - 4 = 48 cards are Not an Ace -----> b = 48
"c" represents the points you receive if Not an Ace is picked. It is given that you lose 1 point ----> c = -1
Answer:
Here is the rest of the page
Step-by-step explanation:
A shopping centre wants to examine the amount of space required for parking. Studies indicated that 50% of staff and shoppers use public transportation. A survey of 1002 was taken, and 483 responded that they used public transportation. At 5% level of significance, is it reasonable to conclude that the survey results indicate a change?
Answer:
We accept H₀ data from the survey is not enough to claim that 50% of the proportion indicated in previous studies have change
Step-by-step explanation:
To get conclusions about the survey we need to develop a hypothesis test of proportion
According to previous studies, (p₀ ) 50 % of staff and customers use public transportation, and we got from a survey 0f 1002 people 483 responded they also use then p = 483/1002 then
n sample size is 1002 and p = 0,482 (48,2 % )
Test Hypothesis
Null hypothesis H₀ p = p₀
Alternative hypothesis Hₐ p < p₀
CI = 95 % α = 5 % α = 0,05 and from z-table we find z score for that value z(c) = - 1,64
z(s) = ( p - p₀ ) / √ (p₀*q₀)/ n p₀ = q₀ = 0,5
z(s) = - 0,018* 31,65 / 0,5
z(s) = - 1,1394
To compare
z(s) and z(c) -1,1394 > 1,64
Then z(s) is inside the acceptance region. We accept H₀ , because we don´t have enough evidence to claim that the survey results indicate a change in
the original proportion
The given line segment has a midpoint at (−1, −2). On a coordinate plane, a line goes through (negative 5, negative 3), (negative 1, negative 2), and (3, negative 1). What is the equation, in slope-intercept form, of the perpendicular bisector of the given line segment? y = −4x − 4 y = −4x − 6 y = One-fourthx – 4 y = One-fourthx – 6
Answer:
y = -4x - 6.
Step-by-step explanation:
We are given (-5, -3), (-1, -2), and (3, -1) for points of a line. First, we need to find the slope.
(-2 - -3) / (-1 - -5) = (-2 + 3) / (-1 + 5) = 1 / 4.
A perpendicular bisector would have a slope of -4, which is the negative reciprocal of 1/4.
Now that we have the slope, we can say that the equation is y = -4x + b. To find what is b, we can say that y = -2 and x = -1.
-2 = -4(-1) + b
-2 = 4 + b
b + 4 = -2
b = -6
So, the equation of the perpendicular bisector is y = -4x - 6.
Hope this helps!
Answer:
y = -4x - 6.
Step-by-step explanation:
Just took the test and got it right
a milha eh uma unidade usada para medir distancias. ela equivale a cerca de 1,6 quilometros. se cada carro percorrer 240 quilometros, quantas milhas tera percorrido? urgente
Classica aplicação de regra de 3:
é dito que: 1 milha = 1,6km
Logo, eis a regra de 3:
milha km
1 -------- 1,6
X -------- 240
1,6X = 240.1
X = 240/1,6
X = 150milhasLogo 240km equivalem a 150milhas
graph the linear equation. Find three points that solve the equation, the plot them on the graph. -2y= 5x +11
Answer:
Three points are (0,-5.5), (-1,-3), (-2.2,0) and graph is shown below.
Step-by-step explanation:
The given equation is
[tex]-2y=5x+11[/tex]
We need to find three points that solve the equation.
Put x=0,
[tex]-2y=5(0)+11[/tex]
[tex]-2y=11[/tex]
[tex]y=-5.5[/tex]
Put x=-1,
[tex]-2y=5(-1)+11[/tex]
[tex]-2y=6[/tex]
[tex]y=-3[/tex]
Put y=0,
[tex]-2(0)=5x+11[/tex]
[tex]5x=-11[/tex]
[tex]x=-2.2[/tex]
So, three points (0,-5.5), (-1,-3) and (-2.2,0) are the solutions of the given equation.
Plot these points on a coordinate plane and connect them by a straight line as shown below.
If the half-life of cesium-137 is 30 years, find the decay constant, r. (Round your answer to nine decimal places.)
Answer:
r = 0.023104906
Step-by-step explanation:
Given half life = T = 30 yrs.
Decay constant = r.
Using the decay constant formula:
[tex]r=\frac{\ln2}{T}\\r=\frac{\ln2}{30}\\r=0.023104906[/tex]
Learn more: https://brainly.com/question/1594198
what's the equation that represents the new path
Answer:
A: y= 1/4x - 7
if it is perpendicular, then it creates 4 right angles. so that new line would pass through (0,-7) and something else that isnt important. but the slope, or m, would be 1/4, and the y intercept would be -7. so the new equation is y=1/4x-7
Help and show work plz
Answer:
30
Step-by-step explanation:
If we have 4 integers that have an average of 9, then all the numbers will add up to [tex]9\cdot4=36[/tex].
If we want the greatest number possible, the other 3 need to be the lowest possible.
Since they are all different, the lowest possible values of the first 3 numbers are 1, 2, and 3.
[tex]1 + 2 + 3 = 6[/tex]
[tex]36 - 6 = 30[/tex]
So 30 is the greatest value of one of the integers.
Hope this helped!
Problem 1. (1 point) A steel ball weighing 128 pounds is suspended from a spring. This stretches the spring 128101 feet. The ball is started in motion from the equilibrium position with a downward velocity of 2 feet per second. The air resistance (in pounds) of the moving ball numerically equals 4 times its velocity (in feet per second) . Suppose that after t seconds the ball is y feet below its rest position. Find y in terms of t. (Note that this means that the positive direction for y is down.)
Answer:
seeed
Step-by-step] explanation:
ddd~!`
Simplify the expression. Write the answer using scientific notation.
(5x107)(6x104)
A) 1.1 x 1012
B) 3.0x 1029
C) 3.0 x 1012
D) 1.1 x 1029
Answer:
3* 10 ^12
Step-by-step explanation:
(5x10^7)(6x10^4)
Multiply the numbers together
5*6 =30
Add the exponents
10^7 * 10 ^ 4 = 10 ^(7+4) = 10 ^11
30 * 10 ^11
But this is not scientific notation since 30 >10
Move the decimal one place to the left and add 1 to the exponent
3* 10 ^12
Answer:
3* 10 ^12
Step-by-step explanation:
Which of the following expression is equal to X^2+9
Answer:
(x + 3i) * (x - 3i) = x^2 + 3xi - 3xi - 9(i^2) = x^2 + 9
Step-by-step explanation:
General solution of equation sin x + sin 5x = sin 2x + sin 4x is
Answer:
x=nπ3, n∈I
Step-by-step explanation:
sin x + sin 5x = sin 2x + sin 4x
⇒⇒ 2 sin 3x cos 2x = 2 sin 3x cos x
⇒⇒ 2 sin 3x(cos 2x - cos x) = 0
⇒ sin 3x=0 ⇒ 3x=nπ ⇒ x=nπ3⇒ sin 3x=0 ⇒ 3x=nπ ⇒ x=nπ3 , n∈I, n∈I
or cos 2x−cos x=0 ⇒ cos 2x=cos xcos 2x-cos x=0 ⇒ cos 2x=cos x
⇒ 2x=2nπ±x ⇒ x=2nπ, 2nπ3⇒ 2x=2nπ±x ⇒ x=2nπ, 2nπ3 , n∈I, n∈I
But solutions obtained by x=2nπx=2nπ , n∈I, n∈I or x=2nπ3x=2nπ3 , n∈I, n∈I are all involved in x=nπ3x=nπ3 , n∈I
How would you find the coefficient of the third term in (x+5)^7?
Answer:
The answer is option B
Step-by-step explanation:
To find the coefficient of the third term in
[tex](x + 5)^{7} [/tex]
Rewrite the expansion in the form
[tex](a + x)^{n} [/tex]
where n is the index
So we have
[tex] ({5 + x})^{7} [/tex]
After that we use the formula
[tex]nCr( {a}^{n - r} ) {x}^{r} [/tex]
where r is the term we are looking for
For the third term we are looking for the term containing x²
that's
r + 1 = 3
r = 2
So to find the coefficient of the third term
We have
[tex]7C2[/tex]
Hope this helps you
first of all, the notation is wrong it should be [tex] {}^nC_r \text{ and more usual notation is } {n \choose k} [/tex]
second, the
[tex](r+1)^{\text{th}} \text{ term } T_{r+1} \text{ in the expansion of } (x+a)^n \text{ is } {n \choose r}x^{(n-r)}a^r[/tex]
here [tex] a=5 \text{ and } n=7 \text{ and for } 3^{\text{rd}} \text{ term } T_3, \quad r+1=3 \implies r=2 [/tex]
so the coefficient of third term is, [tex]{7 \choose 2}={7\choose 5}[/tex]
an important property of binomial coefficient you should know:
[tex] {n \choose k}={n \choose {n-k}}[/tex]
and if you interchange [tex] x \text{ and } a[/tex]
only the "order" will get reversed. i.e. the series will start from back.
another thing, the [tex] k^{\text{th}} \text{ term from beginning, is the } (n-k+2)^{\text{th}} \text{ term from behind}[/tex]
