Use a double-angle or half-angle identity to find the exact value of each expression?
Answers
If 0 < θ < π/2, then 0 < θ/2 < π/4, and for such angles we expect sin(θ/2) to be positive. Also, we know both sin(θ) and cos(θ) will be positive.
Given that tan(θ) = 2, we can find sec(θ) from the Pythagorean identity:
tan²(θ) + 1 = sec²(θ) ==> sec(θ) = √(tan²(θ) + 1)
… ==> cos(θ) = 1/√(tan²(θ) + 1)
… ==> cos(θ) = 1/√5
Now, recall the half-angle identity for sine:
sin²(θ/2) = (1 - cos(θ))/2
==> sin(θ/2) = √[(1 - cos(θ))/2]
==> sin(θ/2) = √[(1 - 1/√5)/2]
==> sin(θ/2) = √[(√5 - 1)/(2√5)]
==> sin(θ/2) = √[(5 - √5)/10]
Related Questions
Write down a decimal that is more than 7/11 and less than 7/9
will award brainiest!!
Answers
Answer:
0.7
Step-by-step explanation:
7/11 = 0.63636363
7/9 = 0.777777778
so a decimal between them will be, 7/10 = 0.7
Christa needs to make a painting for art class.
She can only choose two of the eight colors listed
in the table above. What is the probability the two
colors she chooses are green and purple?
Answers
Because it is a
1/8 she gets green and a 1/8 she gets purple after so u multiply and get 1/64
what is the bionomial expansion of (x-1y)^2
Answers
Answer:
[tex] {(x - y)}^{2} \\ = (x - y)(x - y)[/tex]
open the brackets:
[tex] = ( {x}^{2} - xy - xy + {y}^{2} ) \\ = {x}^{2} - 2xy + {y}^{2} [/tex]
56 is less than the square of 10
Answers
From the given condition, we get X = X^2–56
=> X^2-X-56=0
Factorizing the above equation,
=> X^2–8X+7X-56=0
X(X-8)+7(X-8)=0
(X-8)(X+7)=0
X=8 or -7
Since it is said the number is positive. Our output number will be 7
PLEASE HELP QWQ AsAp with these 4 questions
Answers
Answer:
Step-by-step explanation:
I can't believe I'm doing this for 5 points, but ok!
For the first 3, we are going to multiply to find the value of that 3 x 3 matrix by picking up the first 2 columns and plopping them down at the end and then multiplying through using the rules for multiplying matrices:
[tex]\left[\begin{array}{ccccc}7&4&6&7&4\\-4&8&9&-4&8\\1&8&7&1&8\end{array}\right][/tex] and from there find the sum of the products of the main axes minus the sum of the products of the minor axes, as follows (I'm not going to state the process in the next 2 problems, so make sure you follow it here. This is called the determinate. The determinate is what you get when you evaluate or find the value of a matrix. Just so you know):
[tex](7*8*7)+(4*9*1)+(6*-4*8)-[(1*8*6)+(8*9*7)+(7*-4*4)][/tex] which gives us:
392 + 36 - 192 - [48 + 504 - 112] which simplifies to
236 - 440 which is -204
On to the second one:
[tex]\left[\begin{array}{ccccc}-8&-4&-1&-8&-4\\1&7&-3&1&7\\8&9&9&8&9\end{array}\right][/tex] and multiplying gives us
[tex](-8*7*9)+(-4*-3*8)+(-1*1*9)-[(8*7*-1)+(9*-3*-8)+(9*1*-4)][/tex] which gives us:
-504 + 96 - 9 - [-56 + 216 - 36] which simplifies to
-417 - 124 which is -541, choice c.
Now for the third one:
[tex]\left[\begin{array}{ccccc}-2&-2&-5&-2&-2\\2&7&-3&2&7\\8&9&9&8&9\end{array}\right][/tex] and multiplying gives us
[tex](-2*7*9)+(-2*-3*8)+(-5*2*9)-[(8*7*-5)+(9*-3*-2)+(9*2*-2)][/tex] which gives us:
[tex]-126+48-90-[-280+54-36][/tex] which simplifies to
-168 - (-262) which is 94, choice c again.
Now for the last one. I'll show you the set up for the matrix equation; I solved it using the inverse matrix. So I'll also show you the inverse and how I found it.
[tex]\left[\begin{array}{cc}-4&-5&\\-6&-8\\\end{array}\right][/tex] [tex]\left[\begin{array}{c}x\\y\\\end{array}\right][/tex] = [tex]\left[\begin{array}{c}-5\\-2\\\end{array}\right][/tex] and I found the inverse of the 2 x 2 matrix on the left.
Find the inverse by:
* finding the determinate
* putting the determinate under a 1
* multiply that by the "mixed up matrix (you'll see...)
First things first, the determinate:
|A| = (-4*-8) - (-6*-5) which simplifies to
|A| = 32 - 30 so
|A| = 2; now put that under a 1 and multiply it by the mixed up matrix. The mixed up matrix is shown in the next step:
[tex]\frac{1}{2}\left[\begin{array}{cc}-8&5\\6&-4\end{array}\right][/tex] (to get the mixed up matrix, swap the positions of the numbers on the main axis and then change the signs of the numbers on the minor axis). Now we multiply in the 1/2 to get the inverse:
[tex]\left[\begin{array}{cc}-4&\frac{5}{2}\\3&-2\\\end{array}\right][/tex] Multiply that inverse by both sides of the equation. This inverse "undoes" the matrix that's already there (like dividing the matrix that's already there by itself) which leaves us with just the matrix of x and y. Multiply the inverse matrix by the solution matrix:
[tex]\left[\begin{array}{c}x&y\end{array}\right] =\left[\begin{array}{cc}-4&\frac{5}{2} \\3&-2\end{array}\right] *\left[\begin{array}{c}-5&-2\\\end{array}\right][/tex] and that right side multiplies out to
x = 20 - 5 which is
x = 15 and
y = -15 + 4 which is
y = -11
(It works, I checked it)
A trapezoid has two basses that measure 11 cm and 8 cm. The height of the figure is 5 cm. What is the area of the trapezoid? A) 95 cm2. B) 64 cm2. C) 47.5 cm2. D) 24 cm2
Answers
Answer:
C.47,5cm²
Step-by-step explanation:
The divisibility rule for 7 says 10a + b is a multiple of 7 if only and only if a - 2b is a multiple of 7
Explain.
Answers
Answer:
Step-by-step explanation:
Well I can show you by example. Try 28
a = 2
b = 8
2 - 2*8 = 2 - 16 = -14
- 14 is divisible by 7. You get - 2.
That means that 28 is also divisible by 8
We'll try one more. Try 56
a = 5
b = 6
5 - 2*6 = 5 - 12 = - 7
- 7 is divisible by 7 so 56 must be as well. What I'm wondering is if the rule in some form works for 735 and if it does how?
a = 73
b = 5
73 - 10 = 63
63 is divisible by 7 (giving 9)
so 10*73 + b is divisible by 7.
Try something a bit harder.
115444
a = 11544
b = 4
a - 2*4
11544 - 8
11536 / 7
1648 which works perfectly.
115444 is divisible by 28 which is a multiple of 7
Really amazing! Thanks for posting.
please help me Find DE.
Answers
Answer:
DE = 11
Step-by-step explanation:
DF = DF +EF
4x+2 = x+7 + 7
Combine like terms
4x+2 = x+14
Subtract x from each side
4x+2-x = x+14-x
3x+2 = 14
Subtract 2 from each side
3x+2-2 =14-2
3x=12
Divide by 3
3x/3 = 12/3
x = 4
DE = x+7 = 4+7 =11
Answer:
DE is 11
Step-by-step explanation:
[tex]DE = DF - EF \\ DE = (4x + 2) - 7 \\DE = 4x - 5 [/tex]
But for x:
[tex]4x + 2 = (x + 7) + 7 \\ 4x + 2 = x + 14 \\ 3x = 12 \\ x = 4[/tex]
Therefore:
[tex]DE = (4 \times 4) - 5 \\ = 16 - 5 \\ = 11[/tex]
WILL GIVE BRAINLIEST PLS HELP
Answers
Answer:
Hello
Step-by-step explanation:
[tex]y=2x^2-12x+19\\=2(x^2-6x)+19\\=2(x^2-2*3*x+9)+19-18\\=2(x-3)^2+1\\\\Vertex\ is\ (3,1)\\\\Axis\ of\ symmetry\ is\ x=3\\\\y-intercept\ is \\\\y=2(0-3)^2+1=19\\[/tex]
which is odd one out 4:10 12:25 20:50 8:20
Answers
Answer:
All of them except 12:25 simply to 2:5. So 12:25 is the odd one out.
if set a is 12345 and Set B is 23 find a union B and find a intersection b
Answers
Answer:
a union b= {1,2,3,4,5}
a intersection b ={2,3}
Step-by-step explanation:
The union of two sets A and B is a set that contains all the elements of A and B and is denoted by A U B
the set composed of all elements that belong to both A and B is A intersection B (A ∩ B)
Which graph represents the solution set to the following system of linear
inequalities?
ys2x+7
y>-3x-2
PLSS HELP!
Answers
Answer:
Step-by-step explanation:
I am not sure what your first inequality is saying y≤2x +7 or y≥2x+7
-the equation y> -3x-2 , has a negative slope m= -3 (the line is going down from left to right if is a negative slope) and it has to be a dotted line( <, or > is a dotted line, ≤, or ≥ is a solid line) so the answer must be either A or D
-if the second equation is y≤2x +7 then the answer is D because y has to be less than 2x+7 the area under the line will be include in the solution
--if the second equation is y≤2x +7 then the answer is A because y has to be greater than 2x+7 the area above the line will be include in the solution
Answer:
1 4/5
Step-by-step explanation:
2x+7>-3x-2
2x+3x>-2-7
5x/5>-9/5
=1 4/5
Thanks Hope It Help
which one is the right answers
Answers
Answer:
B
Step-by-step explanation:
n is the number of litres.
if you substitute 1 for 'n' then you will get :
C = 8 + 1.5(1)
C = $9.5
$9.50 for every litre
Answer:
C is correct
Step-by-step explanation:
The $8 charge is only once regardless of how many liters are ordered, so only answer C works.
if √x-5 varies directly as y and x=30 when y= 2, find the value of x when y=8.
Answers
Answer:
let,
√x-5=ky
x=30 when y=2
√30-5=2k
or, k=(√30-5)/2
now, when y=8
√x-5=8×(√30-5)/2
or, √x-5=4√30-20
or, √x=4√30-15
or, x=(4√30-15)²
or, x=47.73..
Miguel can use all or part of his $25 gift card to make a music purchase. Each song costs $1.50, and there is a $1.00 per account activation fee.
Which inequalities can represent this situation if m is the number of songs he can buy? Select two options.
1 + 1.5 m less-than-or-equal-to 25
Answers
Answer:
A, E or 1, 5
Step-by-step explanation:
Its not A, D
What is his weekly allowance if he ended with $15?
Answers
What is the solution, if any, to the inequality |3x|20?
all real numbers
solution
no
x>0
x
Answers
Answer:
20×2=40bnmcsshjvghjpiutewqadgjlmbcz
Answer: all real numbers
Step-by-step explanation:
In January Mr.Tan's students read 20 books. In February, they read 15 books. What is the percent increase or decrease in the number of books the read?
Answers
Answer:
there is a 25% decrease in books being read
For the function f(x)=x+9/7-4x find f^-1(x)
Answers
Answer:
Step-by-step explanation:
[tex]f(x)=\frac{x+9}{7-4x} \\put ~f(x)=y\\flip~x~and~y\\f(y)=x\\y=f^{-1}(x)\\y=\frac{x+9}{7-4x} \\flip~x~and~y\\x=\frac{y+9}{7-4y} \\x(7-4y)=y+9\\7x-4xy=y+9\\-4xy-y=9-7x\\or\\4xy+y=7x-9\\y(4x+1)=7x-9\\y=\frac{7x-9}{4x+1} \\or~f^{-1}(x)=\frac{7x-9}{4x+1}[/tex]
HELPPP HELP PLS PRONTO ASAP
Ahmed is working at a restaurant. His boss pays him $16.00 per hour and
promises a raise of $1.25 per hour every 6 months. Which sequence
describes Ahmed's expected hourly wages, in dollars, starting with his current
wage?
Answers
Answer:
B
Step-by-step explanation:
each of the numbers is just adding 1.25 on to it
Answer: Choice B
16.00, 17.25, 18.50, 19.75, ...
==========================================================
Explanation:
We start with $16.00 as the first term, as this is the amount the boss pays him initially. Then we add on 1.25 to get 16+1.25 = 17.25 to represent the next wage after that first raise.
Then after the second raise he gets, he'll then earn 17.25+1.25 = 18.50 an hour. This process theoretically can go on forever, but realistically the boss will likely set some kind of limit.
We say that this sequence { 16.00, 17.25, 18.50, 19.75, ... } is arithmetic with the first term of 16.00 and common difference 1.25
The common difference is the gap width between any two neighboring terms, and it's the amount the wage goes up each time he gets a raise.
If the function f is given by f(x)= 4x -3, find the value of f(2+h)
Answers
[tex]\\ \sf\longmapsto f(2+h)[/tex]
[tex]\\ \sf\longmapsto 4(2+h)-3[/tex]
[tex]\\ \sf\longmapsto 4h+8-3[/tex]
[tex]\\ \sf\longmapsto 4h+5[/tex]
A lemonade recipe calls for 1/4 cups of lemon juice for every cup of water.
Plot the pairs in the table in a coordinate plane
Answers
Answer:
they are in order cross x with the y across from it
Step-by-step explanation:
The number n is doubled and then has y added to it. The result is then divided by 2 and has the number n subtracted from it, the final result is
Answers
Answer:
[tex]\frac{y}{2}[/tex]
Step-by-step explanation:
n is doubled: 2n
y added: 2n + y
divided by 2: n + [tex]\frac{y}{2}[/tex]
n subtracted -> final resutl: [tex]\frac{y}{2}[/tex]
Brady scored a total of 320 points last season for his basketball team. This season, the team
added 2 extra games to the schedule. Brady thinks this will allow him to increase the total
number of points he scores by 5%. How many points is Brady expecting to score this season?
a. 336
b. 325
c. 304
d. 16
Answers
x²+10x+25resove into factors.
Answers
Answer:
(x + 5)(x + 5)
Step-by-step explanation:
[tex]x^2+10x+25\\(x+5)(x+5)[/tex]
Answer:
(x+5)(x+5)
Step-by-step explanation:
x²+10x+25
x²+5x+5x+25
x(x+5)+5(x+5)
(x+5)(x+5)
BRAINLIEST
HOW CAN POSTULATES AND THEOREMS RELATING TO SIMILAR AND CONGRUENT ANGLES BE USED TO WRITE A PROOF?
Answers
Answer:
How can postulates and theorems relating to similar and congruent triangles be used to write a proof? If the three sets of corresponding sides of two triangles are in proportion, the triangles are similar. ... If the three sets of corresponding sides of two triangles are in proportion, the triangles are similar.
Step-by-step explanation:
Hope this helps :D good luck!!
A set of composite number less than 12.Express it in listing and set-builder methods
Answers
composite numbers less than 12={1,3,4,6,8,9,10}
A shopkeeper marked the price of an article a certain percent above the cost price and he allowed 16% discount to make 5% profit. If a customer paid Rs 9,492 with 13% VAT to buy the article, by what percent is the marked price above the cost price of the article?
Plz solve this problem
Answers
Answer:
25%
Step-by-step explanation:
let the MP be x
sp without vat =x-16%of x
= 21x/25
sp with VAT = 21x/25 +13% of 21x/25
rs 9492 = 2373x/2500
( 9492*2500)/2373=x
x = 10000
cp = ((21x/25 )*100)/100+5 ( 5= profit percent )
=8000
(10000-8000)×100%/8000
=25%
A circle has a radius of 8cm. An angle of 1.4 radians is subtended at the center by an arc. Calculate the length of the arc
Answers
Answer:
11.2 cm
Step-by-step explanation:
Given that;
Arc Length Formula (if θ is in radians): l = ϴ × r
ϴ = angle subtended in radians
r= radius of the circle
l = 8cm × 1.4 radians
l= 11.2 cm
Divide : 12a²b³ 6a²b by 3ab
Answers
Answer:
easy
Step-by-step explanation:
4ab³6a²b
Answer:
[tex] \frac{12 {a}^{2} {b}^{3} 6 {a}^{2}b }{3ab} \\ thank \: you[/tex]
