Question

Use logarithmic differentiation to find the derivative with respect to x of the function y= (sin x)^lnx

Answer 1

Logarithmic differentiation means tAke logarithm of both sides to make the function easier to find the derivative.

y = (sinx)^lnx

ln(y) = ln((sinx)^lnx)

power rule logarithm

ln(y) = ln(x) ln(sinx)

Take derivative

y'/y = ln(sinx)(1/x) + ln(x) cosx/sinx

multiply both sides by y

y' = y( ln(sinx)/x + ln(x)cotx )

remember y = (sinx)^lnx
sub this in for y

y' = (ln(sinx)/x + ln(x)cotx)(sinx)^lnx