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
:


Answer:
See below.
Step-by-step explanation:
-7(6) = -42
-1(-10) = 10
2(-5) = -10
-3(-14) = 42
-32/-4 = 8
-2(-2)(-2) = -8
Answer:
Step-by-step explanation:
4x - 8 = 2x - 10
2x - 8 = -10
2x = -2
x = -1
y = 4(-1) - 8 = -4 -8 = -12
(-1, -12)
Answer:
21+4
Step-by-step explanation:
3 times 7=21
3 times4=12
21d+4e
-8+b2-(5+b2). Since the - is outside the paranthesis the signs inside change: -8+b2-5-b2. -8-5=-3, b2-b2=0. Your answer: -3 :)