Saved Bookmarks
| 1. |
\cos 6 x = 32 \cos ^ { 6 } x - 48 \cos ^ { 4 } x + 18 \cos ^ { 2 } x - 1 |
|
Answer» cos6x=cos[2(3x)]=2cos^2(3x)-1 cos2x=2cos^2x-1 =2[cos(3x)]^2-1 cos3x=4cos^3x-3cosx =2[4cos^3x-3cosx]^2-1 (a-b)^2=a^2+b^2-2ab =2[16cos^6x+9cos^2x-24cos^4x]-1 =32cos^6x-48cos^4x+18cos^2x-1 |
|