x³ + 2x² - x - 2 < 0
x³ - x + 2x² - 2 < 0
x(x² - 1) - 2(x² - 1) < 0
(x - 2)(x² - 1) < 0
(x - 2)(x - 1)(x + 1) < 0
by chacking we get the solution
x ∈ (-∞,-1) ∪ (-1,1)
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:
x=0
Step-by-step explanation:
We are given:
g(x) =10x +2
and
g(x)=2
g(x) is equal to both 10x+2 and 2. Therefore, by substitution, we can set them equal to each other
10x+2=2
Now, we need to solve for x. First, move all the numbers to the same side. Subtract 2 from both sides
10x+2-2=2-2
10x=0
To solve for x, we have to get x by itself. x and 10 are being multiplied. To get x alone, divide both sides by 10.
10x/10=0/10
x=0