How do you differentiate y=x^(8x)?

1 Answer
Apr 18, 2016

Use logarithmic differentiation (or its equivalent exponential form).

Explanation:

y=x^(8x)

Logarithmic Differentiation

Take the logarithm of both sides.

lny=ln(x^(8x))=8xlnx. Now differentiate implicitly.

1/y dy/dx = 8lnx+8x(1/x) = 8lnx+8

dy/dx = y(8lnx+8) = x^(8x)(8lnx+8).

Exponential Equivalent

y=x^(8x) = e^(ln(x^(8x))) = e^(8xlnx)

Differentiate using d/dx(e^u) = e^u(du)/dx

dy/dx = e^(8xlnx)(8lnx+8)

= x^(8x)(8lnx+8)