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
:


The standard form of the quadratic equation is ax^2 + bx + c. In vertex form, it's y = a(x – h)2 + k.
The graph of a quadratic equation is a parabola, which looks like a u. If <em>a</em> is negative then it's an upside down u.
Answer:
slope = 2/3
Step-by-step explanation:
Answer:
N + 7 = 12
Step-by-step explanation:
When you have a number minus a negative number, it's the same as addition.
Answer:
A rectangular prism in which BA = 20 and h = 6 has a volume of 120 units3; therefore, Shannon is correct
Step-by-step explanation:
step 1
Find the area of the base of the rectangular pyramid
we know that
The volume of the rectangular pyramid is equal to

where
B is the area of the base
H is the height of the pyramid
we have


substitute and solve for B



step 2
Find the volume of the rectangular prism with the same base area and height
we know that
The volume of the rectangular prism is equal to

we have


substitute

therefore
The rectangular prism has a volume that is three times the size of the given rectangular pyramid. Shannon is correct