Recall the half-angle identity:
cos²(x) = 1/2 (1 + cos(2x))
Let x = 75°, so that 2x = 150°. Then
cos²(75°) = 1/2 (1 + cos(150°))
You might already be aware that cos(150°) = -√3/2, so
cos²(75°) = 1/2 (1 - √3/2)
cos²(75°) = 1/2 - √3/4
cos²(75°) = (2 - √3)/4
But this is the square of the number we want, which we solve for by taking the square root of both sides. This introduces a second solution, however:
cos(75°) = ± √[(2 - √3)/4]
cos(75°) = ± √(2 - √3)/2
75° falls between 0° and 90°, and you should know that cos(x) is positive for x between these angles. This means cos(75°) must be positive, so we pick the positive root:
cos(75°) = √(2 - √3)/2
Hi :)
Equation : 
First Add 13 to both sides
The second step is to divide both sides by 8
We have our answer
Learn more;work harder
<u>Answer:</u>
m² - 3m - 10
<u>Steps:</u>
(m + 2)(m – 5) = m² - 5m + 2m - 10
(m + 2)(m – 5) = m² - 3m - 10
Any number raised to the power of 0 is 1.
(z^3)^4(q^3)^0 = (z^3)^4 = z^(3 x 4) = z^12
