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3 years ago

Use the sum and difference identities to find the exact values of the sine, cosine, and tangent of the angle. . 165 = 135 + 30

1 answer:

4 0

So lets get to the problem

165°= 135° +30° 

To make it easier I'm going to write the same thing like this 
165°= 90° + 45°+30° 

Sin165° 
= Sin ( 90° + 45°+30° ) 
= Cos( 45°+30° )..... (∵ Sin(90 + θ)=cosθ 
= Cos45°Cos30° - Sin45°Sin30° 

Cos165° 
= Cos ( 90° + 45°+30° ) 
= -Sin( 45°+30° )..... (∵Cos(90 + θ)=-Sinθ 
= Sin45°Cos30° + Cos45°Sin30° 

Tan165° 
= Tan ( 90° + 45°+30° ) 
= -Cot( 45°+30° )..... (∵Cot(90 + θ)=-Tanθ 
= -1/tan(45°+30°) 
= -[1-tan45°.Tan30°]/[tan45°+Tan30°] 

Substitute the above values with the following... These should be memorized 
Sin 30° = 1/2 
Cos 30° =[Sqrt(3)]/2 
Tan 30° = 1/[Sqrt(3)] 
Sin45°=Cos45°=1/[Sqrt(2)] 
Tan 45° = 1

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-4.7 divided by 1\4 ????????????????

Nady [450]

Answer:

-18.8

Step-by-step explanation:

1/4 as a decimal is 0.25 so then if you divide -4.7 by 0.25 the answer is -18.8 :)

I hope this helped :)

3 0

3 years ago

Read 2 more answers

What is 26/4, 6.45, 6 2/5, and 50/8 in order from least to greatest?

blagie [28]

26/4=6.50

6.45=6.45

6and 2/5=6.40

50/8=6.25

so it should be

least- greatest

50/8, 6 & 2/5, 6.45, 26/4

7 0

3 years ago

PLS HELP ILL GIVE BRAINLIEST

inysia [295]

<h3>Answer: 14x - 8</h3>

=======================================================

Explanation:

I'll use the quadratic formula to find the roots or x intercepts. This slight detour allows us to factor without having to use guess-and-check methods.

The equation is of the form ax^2+bx+c = 0

a = 12
b = -11
c = -5

This leads to...

$x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\\\\x = \frac{-(-11)\pm\sqrt{(-11)^2-4(12)(-5)}}{2(12)}\\\\x = \frac{11\pm\sqrt{361}}{24}\\\\x = \frac{11\pm19}{24}\\\\x = \frac{11+19}{24} \ \text{ or } \ x = \frac{11-19}{24}\\\\x = \frac{30}{24} \ \text{ or } \ x = \frac{-8}{24}\\\\x = \frac{5}{4} \ \text{ or } \ x = -\frac{1}{3}$

Now use those roots to form these steps

$x = \frac{5}{4} \ \text{ or } \ x = -\frac{1}{3}\\\\4x = 5 \ \text{ or } \ 3x = -1\\\\4x - 5 =0 \ \text{ or } \ 3x+1 = 0\\\\(4x-5)(3x+1) = 0$

Refer to the zero product property for more info.

Therefore, the original expression factors fully to (4x-5)(3x+1)

Use the FOIL rule to expand it out and you should get 12x^2-11x-5 again.

----------------------------------------------

We did that factoring so we could find the side lengths of the rectangle.

I'm using the fact that area = length*width

L = length = 4x-5
W = width = 3x+1

The order of length and width doesn't matter.

From here, we can then compute the perimeter of the rectangle

P = 2(L+W)

P = 2(4x-5+3x+1)

P = 2(7x-4)

P = 14x - 8

6 0

2 years ago

for an acute angle 0, the equation sin(0) the equation sin(0) = cos(6) is true. What is the value of 0?

11111nata11111 [884]

The answer for the value of 0 is 0=1

8 0

2 years ago

Find an equation for the inverse for each of the following.

IgorLugansk [536]

Answer:

To solve these first swap x and y, solve for y and name it inverse function

3. y = -8x + 2

x = -8y + 2
8y = -x + 2
y = -x/8 + 2/8
y = -(18)x + 1/4

f⁻¹(x) = -(18)x + 1/4

-----------------------------------------

4. y = (2/3)x - 5

x = (2/3)y - 5
(2/3)y = x + 5
y = (3/2)x + (3/2)5
y = 1.5x + 7.5

f⁻¹(x) = 1.5x + 7.5

-----------------------------------------

5. f(x) = 2x² - 6

x = 2y² - 6
2y² = x + 6
y² = 1/2x + 3
y = $\sqrt{1/2x + 3}$

f⁻¹(x) = $\sqrt{1/2x + 3}$

-----------------------------------------

6. y = (x - 3)²

x = (y - 3)²
$\sqrt{x}$ = y - 3
y = 3 + $\sqrt{x}$

f⁻¹(x) = 3 + $\sqrt{x}$

4 0

3 years ago