Question: y= x sin x. Find its derivative.
Use the product rule.
If y = u*v, where u and v are functions of x, then
dy/dx =u*(dv/dx) + v*(du/dx)
Since we have y = x.sinx, where u = x and v = sinx, then
dy/dx = x.(cosx) + sinx.(1)
Answer: dy/dx = sinx + x.cosx