posted by john .
Differentiate both sides of the double angle identify sin 2x= 2 sin x cos x to determine an identify for cos x.
Find the first derivative, second derivative, third fourth, fifth, sixth, seventh and eighth derivative.
Use the results to find the twelfth and fifteenth derivative.
Write an expression for each of the following derivatives
sin 2x= 2 sin x cos x
2cos2x = 2(sinx)(-sinx) + 2cosx(cosx)
cos2x = cos^2 x - sin^2 x
-2sin2x = 2(cosx)(-sinx) -2sinx(cosx)
2cos2x = -2sinx(-sinx) - 2cosx(cosx)
cos2x = sin^2x - cos^2x