Question on Caculus?

Question

find d4f/4x4 if y=x4(x5-2) using leibainty rule?

Answer 1

I guess you mean the 4th derivative of y = x*4 * (x^5-2) = x^9 - x^4. It's well known that the k-th derivative of x^n, k<=n, n<>0, is n(n -1)....(n -k+1) x^(n-k). Therefore,

d^4y/dx^4 = 9*8*7*6 x^5 - 2 * 4*3*2*1 = 3024 x^5 - 48