Answer:
f(x) = 8x⁴-8x²+1
Step-by-step explanation:
I will assume that f(cos θ) = cos(4θ). Otherwise, f would not be a polynomial. lets divide cos(4θ) in an expression depending on cos(θ). We use this properties
- cos(2a) = cos²(a) - sin²(b)
- sin(2a) = 2sin(a)cos(a)
- sin²(a) = 1-cos²(a)
cos(4θ) = cos(2 * (2θ) ) = cos²(2θ) - sin²(2θ) = [ cos²(θ)-sin²(θ) ]² - [2cos(θ)sin(θ)]² = [cos²(θ) - ( 1 - cos²(θ) ) ]² - 4cos²(θ)sin²(θ) = [2cos²(θ)-1]² - 4cos²(θ) (1 - cos²(θ) ) = 4 cos⁴(θ) - 4 cos²(θ) + 1 - 4 cos²(θ) + 4 cos⁴(θ) = 8cos⁴(θ) - 8 cos²(θ) + 1
Thus f(cos(θ)) = 8 cos⁴(θ) - 8 cos²(θ) + 1, and, as a result
f(x) = 8x⁴-8x²+1.
Answer:
The answer is 51+52+53
Step-by-step explanation:
Answer:
7y=14. 2x - 4y = 18. (-3x + 2y = 1 ) 3. 2x+6y=18. -qx+6y=3. -7x=21 y=2. 3x + 5y =-5. 3x +0=-5. X=-3. 3x+2y = 1. 10. -10. -3x + 2y. 9+27='s. 끓들 x=-5. (-5,2) y=-4. 3.
Step-by-step explanation:
x=2(y+3). 3 x - 6 y = 18. 3x−6y=18. Add 6y to both sides. Add 6y to both sides. 3x=18+6y. 3x=18+6y
