What is the derivative of sin (x/2)sin(x2)?

1 Answer
Jun 21, 2016

1/2 cos (x/2)12cos(x2)

Explanation:

if you know that d/dx sin x = cos xddxsinx=cosx then you can use the chain rule so by letting u = x / 2u=x2 you have d/(du) sin u = cos uddusinu=cosu

and (du)/dx = (d)/dx (x/2)= 1/2dudx=ddx(x2)=12

so d/{du} (sin u) \times (du)/(dx) = cos u \times 1/2 = 1/2 cos (x/2)soddu(sinu)×dudx=cosu×12=12cos(x2)