Question

Question #54f40

Answer 1

`1`

Explanation:

Using `sin^2x+cos^2x=1->cos^2x=sinx`

and

`cos^4x(cos^4x+2cos^2x+1)= sin^2x(sinx+1)^2`

but

`sinx = (-1+sqrt(5))/2` then

`cos^8(x)+2cos^6(x)+cos^4(x)=((-1+sqrt(5))/2)^2((-1+sqrt(5))/2+1)^2=1`