Question

what is second derivative of x cos x​

Answer 1

Explanation:

d(d(x cosx))

= d(d(x) cosx + x d(cosx))

= d(cosx - x sinx)

= d(cosx) - d(xsinx)

= -sinx - (d(x) sinx + x d(sinx))

= -sinx - (sinx + x cosx)

= -2sinx - x cosx