2cos^2 x = 1 + cos 2x
cos^2 x = 1/2(1 + cos 2x)
f(x) = 6cos^2 x - 4 sin 2x = 6(1/2(1 + cos 2x) - 4 sin 2x = 3 + 3cos 2x - 4sin 2x
Answer:
The answer is -3x.
Step-by-step explanation:
Combine like terms.
Hope this helps :)
Answer:
x = 3/4 + (3 sqrt(5))/4 or x = 3/4 - (3 sqrt(5))/4
Step-by-step explanation:
Solve for x over the real numbers:
8 x^2 - 12 x - 23 = -5
Divide both sides by 8:
x^2 - (3 x)/2 - 23/8 = -5/8
Add 23/8 to both sides:
x^2 - (3 x)/2 = 9/4
Add 9/16 to both sides:
x^2 - (3 x)/2 + 9/16 = 45/16
Write the left hand side as a square:
(x - 3/4)^2 = 45/16
Take the square root of both sides:
x - 3/4 = (3 sqrt(5))/4 or x - 3/4 = -(3 sqrt(5))/4
Add 3/4 to both sides:
x = 3/4 + (3 sqrt(5))/4 or x - 3/4 = -(3 sqrt(5))/4
Add 3/4 to both sides:
Answer: x = 3/4 + (3 sqrt(5))/4 or x = 3/4 - (3 sqrt(5))/4
