Find value a when the angle between vectors U=(2,a) and V = (-6;8) is pie/4
Answer:
Step-by-step explanation:
The formula to find the angle between 2 vectors is
[tex]cos\theta=\frac{u*v}{|u||v|}[/tex] which is the dot product of u*v over the (magnitude of u times the magnitude of v). We also know that θ = [tex]\frac{\sqrt{2} }{2}[/tex]. Filling in that formula requires us to find the dot product of u and v, which is
u·v = (2×(-6)) + (a×8) so
u·v = -12 + 8a. Then we need the magnitudes of both u and v:
[tex]|u|=\sqrt{2^2+a^2}=\sqrt{4+a^2}[/tex] and
[tex]|v|=\sqrt{(-6)^2+8^2}=\sqrt{100}=10[/tex]
Putting all of together looks like this:
[tex]\frac{\sqrt{2} }{2}=\frac{-12+8a}{10\sqrt{4+a^2} }[/tex] . Cross multiply to get
[tex]10\sqrt{2}(\sqrt{4+a^2})=2(-12+8a)[/tex] which is tricky to simplify. You really need to know the rules for multiplying radicals to do this correctly. The simplification is
[tex]10\sqrt{8+2a^2}=-24+16a[/tex] and we need to solve for a. Begin by squaring both sides to get rid of the square root to get:
100(8 + 2a²) = 256a² - 768a +576 and simplify some more by distributing through the parenthesis to get
800 + 200a² = 256a² -768a + 576. Combine like terms to come up with
0 = 56a² - 768a - 224 and we need to factor that. Assuming since you're this far in math (pre-calc or maybe late algebra 2) you know how to factor, when you do, you get values for a of - .285714... and 14.
Therefore, the value for a is 14. I checked it...it works
Answer:
a = 14, U = (2, 14)
Step-by-step explanation:
the other answer is correct.
just to add the solution path for the quadratic equation
0 = 56a² - 768a - 224
in general, a quadratic equation usually expressed in x
0 = ax² + bx + c
has its solution as
x = (-b ± sqrt(b² - 4ac))/(2a)
for us here this looks like this then
a = (768 ± sqrt(768² - 4×56×-224))/(2×56) =
= (768 ± sqrt(589824 + 4×56×224))/112 =
= (768 ± sqrt(589824 + 50176))/112 =
= (768 ± sqrt(640000))/112 = (768 ± 800)/112
a1 = (768 + 800)/112 = 1568/112 = 14
a2 = (768 - 800)/112 = -32/112 = -0.29
and the negative solution would be for a vector solution in the wrong direction (down instead of up). as V is pointing up left, and the angle is only 45 degrees (pi/4), also U has to point up.
so, 14 is the solution for U.
NO LINKS OR ELSE YOU'LL BE REPORTED!Only answer if you're very good at Math.No guessing please.
Angelo's Pizza is having a ticket raffle to raise money for new soccer uniforms.A $1 ticket gives an even chance to win one $25 gift certificate,one $15 gift certificate,or three $5 gift certificates.What is the expected profit or loss for purchasing 1 ticket if 100 total tickets are sold?
A: a gain of $0.45
B: a gain of $0.55
C: a loss of $0.55
D: a loss of $0.45
===============================================
Explanation:
Let x be the net winnings the customer gets
Saying something like x = 24 means you've walked away with $24. This occurs when you pay $1, and get $25 back in prizes, so 25-1 = 24 dollars overall.
The probability of this event occurring is 1/100 since there's only one ticket with the $25 prize
Make a table as shown below. It represents all the possible x values which are all the possible net winnings. Note how 1/100 = 0.01, 3/100 = 0.03 and 95/100 = 0.95
The third column is x*p(x) which is the product of the first two columns. Adding everything in the third column (that isn't highlighted in yellow) gets us the value -0.45 which is the expected value for the customer.
This represents a loss of $0.45, aka a loss of 45 cents. This is from the perspective of the customer.
Flipping things around, the pizza company will see this is as a gain of $0.45 or a gain of 45 cents.
----------------
Here's another way to see why this works:
The pizza company earns $100 in revenue since 100 tickets are sold for a dollar each. The company pays out 25+15+3*5 = 55 dollars in prizes overall. That means the company will make a profit of 100-55 = 45 dollars. So the average profit per ticket is 45/100 = $0.45 aka 45 cents and this is from the viewpoint of the pizza company (not the customer). The positive average profit represents a gain.
The total cost of a truck rental, y, for x days, can be modeled by y=24x+39. What is the rate of change for this function?
Answer:
24 per day
Step-by-step explanation:
'x' = days, so since 24 is with x, the rate of change is 24
Use the grouping method to factor this polynomial.
x^3 + 2x^2 + 12x +24
A. (x^2+6)(x+2)
B. (x^2 +2)(x+6)
C. (x^2 +2)(x+12)
D. (x^2 +12)(x+2)
Answer:
[tex]( {x}^{2} + 12)(x + 2)[/tex]
Step-by-step explanation:
[tex] {x}^{3} +2 {x}^{2} +12x+24[/tex]
[tex]( {x}^{3}+2 {x}^{2} )+12x+24[/tex]
[tex] {x}^{2} (x+2)+12(x+2)[/tex]
[tex]( {x}^{2} + 12)(x + 2)[/tex]
Hope it is helpful...What is the area of the parallelogram below?
7 in2
14 in2
18 in2
28 in2
Answer:
14 (B)
Step-by-step explanation:
Area = L * h
L = 7 in^2
h = 2
Area = 7 * 2
Area = 14 in^2
Answer:
14
Step-by-step explanation:
Did lesson
A high school has 32 players on the football team. The summary of the players' weights is given in the box plot. Approximately, what is the percentage of players weighing greater than or equal to 233 pounds
Answer:
[tex]\% = 11.96\%[/tex]
Step-by-step explanation:
Given
See attachment for box plot
Required
Percentage greater than or equal to 233
From the box plot, the maximum is:
[tex]Max = 244[/tex]
The minimum is:
[tex]Min = 152[/tex]
Percentage greater than 233 is calculated as:
[tex]\% = \frac{Max - 233}{Max - Min}[/tex]
[tex]\% = \frac{244 - 233}{244-152}[/tex]
[tex]\% = \frac{11}{92}[/tex]
Express as percentage
[tex]\% = \frac{11}{92}*100\%[/tex]
[tex]\% = \frac{1100}{92}\%[/tex]
[tex]\% = 11.96\%[/tex]
William has three $10 bills and four $1 bills in his wallet. What is the probability that he will reach into his wallet twice and pull out a $10 bill each time? Assume he does not replace the first bill when he pulls out the second one.
Answer:
Step-by-step explanation can’t because he might pull out more than 10 dollars or less than 10 dollars.
I need some help on this math question. Please explain how you found the answer too!
Answer:
A
Step-by-step explanation:
The table represents a proportional function which has a rate of proportionality equal to 5
In fact
5:1 = 5
15 : 3 = 5
25 : 5 = 5
35 : 7 = 5
If we make 90 : 18, the result is 5, so this dates can be part of the table
In a certain year, 86% of all Caucasians in the U.S., 77% of all African-Americans, 77% of all Hispanics, and 84% of residents not classified into one of these groups used the Internet for e-mail. At that time, the U.S. population was 64% Caucasian, 11% African-American, and 10% Hispanic. What percentage of U.S. residents who used the Internet for e-mail were Hispanic
Answer:
Percentage of U.S resident who used the Internet for e-mail were Hispanic=9.19%
Step-by-step explanation:
We are given that
Population was Caucasian=64%
Population was African-American=11%
Population was Hispanic=10%
Let the population of U.S=10000
Now,
Population was Caucasian=[tex]\frac{64}{100}\times10000=6400[/tex]
Population was African-American=[tex]\frac{11}{100}\times 10000=1100[/tex]
Population was Hispanic=[tex]\frac{10}{100}\times 10000=1000[/tex]
Population of others=10000-(6400+1100+1000)=1500
Population of Caucasians used the Internet for e-mail=86% of 6400
Population of Caucasians used the Internet for e-mail=[tex]\frac{86}{100}\times 6400[/tex]
Population of Caucasians used the Internet for e-mail=5504
Population of African-American used the Internet for e-mail=77% of 1100
Population of African-American used the Internet for e-mail=[tex]\frac{77}{100}\times 1100=847[/tex]
Population of Hispanics used the Internet for e-mail=77% of 1000
Population of Hispanics used the Internet for e-mail=[tex]\frac{77}{100}\times 1000=770[/tex]
Population of others used the Internet for e-mail=84% of 1500
Population of others used the Internet for e-mail=[tex]\frac{84}{100}\times 1500=1260[/tex]
Total population used the Internet for e-mail=5504+847+770+1260
Total population used the Internet for e-mail=8381
Percentage of U.S resident who used the Internet for e-mail were Hispanic
=[tex]\frac{Population \;of \;Hispanics \;used \;the \;Internet \;for \;e-mail}{total\;population\; used \;the \;Internet \;for\; e-mail}\times 100[/tex]
Percentage of U.S resident who used the Internet for e-mail were Hispanic=[tex]\frac{770}{8381}\times 100[/tex]
Percentage of U.S resident who used the Internet for e-mail were Hispanic=9.19%
Which graph represents the function f(x)=|x|-4?
See the graph in the attached image.
Find the value of x. Round to the nearest 10th
Answer:
44.94
Step-by-step explanation:
How many plants are shorter than 27 inches?
In one season, a basketball player missed 15% of her free throws. How many free throws did she attempt if she made 102 free throws? Write the exact answer. Do not
round
Answer:
120 free throws
Step-by-step explanation:
If she misses 15% of her free throws, that means she makes 85% of them.
Find how many she attempted by dividing 102 by 0.85:
102/0.85
= 120
So, she attempted 120 free throws
The number of free throws that were attempted is 120 free throws.
Since the basketball player missed 15% of her free throws, This means that the percentage scored will be:
= 100% - 15% = 85%
Therefore, 85% of x = 102
0.85x = 102
x = 102/0.85.
x = 120
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What is the smallest counting number that is divisible by 2, 4, 5, 6, and 12? express each number and your final answer as a product of primes. What do you notice?
Answer:
60
[tex]2^{2} * 3 * 5[/tex]
Step-by-step explanation:
A six sided number cube is rolled. What is the probability of getting a 2 and then a 1, given that the first number rolled was a 2?
Answer:
1/36
Step-by-step explanation:
P(2 then 1) = 1/6 x 1/6 = 1/36
There are 924 people in a theatre.
383 of the people are men.
356 of the people are women.
2
of the children are boys.
5
Work out how many girls are in the theatre
[tex]924 - (383 + 356 + 2 + 5 )[/tex]
Answer:
Step-by-step explanation:
total no. of people in the theatre = 924
men=383
women=356
boy children =2
doing workout 5
total=746
no. of girls= 924-746=178
Therefore, the number of girls are in the theatre are 178.
Malik collects rare stamps and has a total of 212 stamps. He has 34 more domestic stamps than foreign stamps. Let x represent the number of domestic stamps and let y represent the number of foreign stamps.
How many foreign stamps does Malik have?
Answer:
answer in picture
c, b, d
Step-by-step explanation:
High School Dropouts
Number of Dropouts
1990
2000
Male
Female
MAMD.M.D.3: Which of the
following is true about the graph?
Answer:
There are more females dropping than males each year and that there are more females than males
PLEASE HELP!
WILL MARK BRAINLIEST!!!
If AC=12cm, what is the area sector ACB to the nearest whole number?
Thank you! Multiple choice!
Answer:
38
Step-by-step explanation:
Have a nice day :)
Help me i think it’s c
Answer: Graph B
=====================================================
Explanation:
Point A appears to be at (2.5, -1)
If we shift 6 units to the left, then we subtract 6 from the x coordinate. So the new x coordinate is now 2.5-6 = -3.5
If we shift 4 units up, then we add 4 to the y coordinate to go from -1 to -1+4 = 3
Overall, the point A(2.5, -1) moves to A'(-3.5, 3)
Graph B is the answer because of this. The other points B and C will follow the same pattern as point A does.
Trong không gian Oxyz, cho a b c 2;2;0 , 2;2;0 , 2;2;2 .
Giá trị của a b c
bằng
Answer:
good question
Step-by-step explanation:
someone please help me answer this
Answer:
77.91 units²
or
77.91 square units
Step-by-step explanation:
the area of a circle is A=pi*r²
since we only need a certain fraction, we will multiply it with 62/360
62° is the given angle. 360° would be the full circle
A = pi * 12² * 62/360
note that the answer is in square units, bc in "r²" the units themselves get squared, even tough we don't know if its inch or kilometers, its definitely squared
Find the indicated area of the sector surrounded in bold.
Answer:
75.36 yd² (≈ 75.4 yd²)
Step-by-step explanation:
GIVEN :-
Angle subtended by the arc at center of circle (θ) = 135°Radius of the circle = 8 ydTO FIND :-
Area of the sectorGENERAL FORMULAE TO BE USED IN THI QUESTION :-
Lets say there's an arc which subtends θ angle in the center of the circle & radius of the circle is 'r'.
Area of the sector = [tex]\frac{\theta}{360} \times \pi r^2[/tex]
SOLUTION :-
Area of the sector = [tex]\frac{\theta}{360} \times \pi r^2[/tex]
[tex]= \frac{135}{360} \times \pi (8)^2[/tex]
[tex]= \frac{3}{8} \times 64 \times 3.14[/tex]
[tex]= 3 \times 8 \times 3.14[/tex]
[tex]=75.36 \; yd^2[/tex]
If the number of orders at a production center this month is a Geom(0.7) random variable, find the probability that we'll have at most 3 orders.
Answer: 0.973
Step-by-step explanation:
The probability mass function of geometric distribution is
[tex]f(x)=(1-p)^{x-1}p,\ \ \ x=1,2,3,...[/tex], p= probability of success on a trial.
As per given, we have
p=0.7
The probability that we'll have at most 3 orders [tex]P(X\leq3)=P(x=1)+P(x=2)+P(x=3)[/tex]
[tex]=(1-0.7)^{1-1}(0.7)+(1-0.7)^{2-1}(0.7)+(1-0.7)^{3-1}(0.7)\\\\=0.7+0.21+0.063\\\\=0.973[/tex]
hence, the required probability = 0.973
The probability that we'll have at most 3 orders will be "0.973".
According to the question,
→ [tex]x \sim Geometric (p)[/tex]
here,
p = 0.7
then,
→ [tex]P(X=x) = (1-p)^{x-1}\times p[/tex]
By putting the given values, we get
[tex]= (1-0.7)^{x-1}\times 0.7[/tex]
hence,
The probability that we'll have at most 3 orders will be:
→ [tex]P(X \leq 3)=P(X=1)+P(X=2)+P(X=3)[/tex]
[tex]=0.7+0.21+0.063[/tex]
[tex]=0.973[/tex]
Thus the above response is correct.
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Element X is a radioactive isotope such that its mass decreases by 73% every
hour. If an experiment starts out with 680 grams of Element X, write a
function to represent the mass of the sample after t hours, where the rate of
change per minute can be found from a constant in the function. Round all
coefficients in the function to four decimal places. Also, determine the
percentage rate of change per minute, to the nearest hundredth of a percent.
Mi
Answer:
Step-by-step explanation:
The element decay percentage rate of change 2.22% per minute.
What is radioactive isotope?
Radioisotope, radionuclide, or radioactive nuclide, any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.
Here, mass decreases by 73% every hour.
Weight of element X is 680 grams.
According to question,
f(t) = 680 (1 - 73%)ⁿ
f(t) = 680 (1 - 0.73)ⁿ
f(t) = 680 X 0.27ⁿ
f(t) = 680 X 0.9778ⁿ
f(t) = 680 X (1 - 0.02322)ⁿ
Thus, the element decay percentage rate of change 2.22% per minute.
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Did I answer this correctly? Drag each tile to the correct box. Not all tiles will be used. Arrange the steps to solve this system of linear equations in the correct sequence.
Put the following in order:
A. Subtract 3x + 3y = -6 (obtained in step 1) from 2x – 3y = -9 (given) to solve for x.
B) Substitute the value of x in the first equation (x + y = -2) to get y = 1.
C) The solution for the system of equations is (-3, 1).
D) x = -15
E) The solution for the system of equations is (-15, 13).
F) Add 3x + 3y = -6 (obtained in step 1) to 2x – 3y = -9 (given), and solve for x.
G) x = -3
H) Substitute the value of x in the first equation (x + y = -2) to get y = 13.
J) Multiply the first equation by 3: 3(x + y) = 3(-2) 3x + 3y = -6.
Remember that only 5 can be used.
9514 1404 393
Answer:
your 3rd step should be x = -3
Step-by-step explanation:
When you combine the equations in step 2, you get ...
5x = -15
Dividing by 5 gives the solution for x:
x = -3
This is what your Step 3 should show. This is the value that is consistent with the remaining steps.
Answer:9514 1404 393
Step-by-step explanation:
sample of one hundred seventy-eight students were surveyed one week prior to the election for student body president
egarding their choice of three candidates. The table below shows the results of the survey.
A
B
С
Candidates
Votes
67
57
54
Use the information above. There are 1571 students in the school. According to the survey, about how many votes can
candidate A expect to recieve?
Answer:
592 Votes
Step-by-step explanation:
According to the Question,
Given That, a sample of 178 students was surveyed one week prior to the election for student body president Regarding their choice of three candidates.The table below shows the results of the survey.A B С
Candidates Votes 67 57 54
And, There are 1571 students in the school.
So, The Total votes can candidate 'A' expect to Receive is⇒(1571/178)×67
⇒591.33 ≈ 592 Votes(Approximately)
Solve the inequality for s:
5s + 2 > 7
Answer:
Answer:
S>1
Step-by-step explanation:
5s + 2 > 7
Subtract 2 from both sides
5s>5
Divide 5 from both sides
S>1
Solution of the inequality is s>1.
What is an inequality?In mathematics, "inequality" refers to a relationship between two expressions or values that is not equal to one another.
Adding the same amount to each side, taking the same amount away from each side, multiplying or dividing each side by the same positive integer, and other operations can be used to solve the inequality.
The inequality sign must be reversed if either side is multiplied or divided by a negative number.
5s+2 > 7
Subtracting 2 on both side,
5s > 5
s>1
Therefore, the solution set of inequality is s>1.
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Parrot eats only ........ products
Answer:
Maybe Plants products...
its my final, please help!!!!!!!!!!
Answer:
both apply
Step-by-step explanation:
i guessed just do it
