Given:

To find:
The exact value of cos 15°.
Solution:

Using half-angle identity:


Using the trigonometric identity: 

Let us first solve the fraction in the numerator.

Using fraction rule: 

Apply radical rule: ![\sqrt[n]{\frac{a}{b}}=\frac{\sqrt[n]{a}}{\sqrt[n]{b}}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7B%5Cfrac%7Ba%7D%7Bb%7D%7D%3D%5Cfrac%7B%5Csqrt%5Bn%5D%7Ba%7D%7D%7B%5Csqrt%5Bn%5D%7Bb%7D%7D)

Using
:


It helps you know what to multiply and the product when you subtracting and adding fractions.
You just need to substitute the the given function. So if f(-8) then you fill in f(n)=2n+4 which would be f(-8)=2(-8)+4. Which is -12.
hope this helps !
Answer/Step-by-step explanation:
Recall: SOHCAHTOA
1. Reference angle = 70°
Adjacent side = x
Hypotenuse = 6 cm
Apply CAH. Thus,
Cos 70 = adj/hyp
Cos 70 = x/6
6 × cos 70 = x
2.05 = x
x = 2.05 cm
2. Reference angle = 45°
Adjacent side = x
Hypotenuse = 1.3 m
Applying CAH, we would have the following ratio:
Cos 45 = adj/hyp
Cos 45 = x/1.3
1.3 × cos 45 = x
0.92 = x
x = 0.92 m
3. The who diagram is not shown well. Some parts are missing, however you can still solve the problem just the same way we solved problem 1 and 2.
Every body has two hands so we have to multiply 66 by 2.
66 multiplied by 2 is equal to 132
The answer is 132.
hope it helps.
Can you choose mine as the brainliest answer <u><em>please please?</em></u>