How do you differentiate y=tan[ln(1-3x)]y=tan[ln(13x)]?

1 Answer
Dec 29, 2017

d/dx[y(u)]=(-3sec^2(ln(1-3x)))/(1-3x)ddx[y(u)]=3sec2(ln(13x))13x

Explanation:

Apply The Chain Rule:

Let color(red)(u=ln(1-3x)u=ln(13x) And rewrite the problem

y=tan[ln(1-3x)]->y=tan(color(red)u)y=tan[ln(13x)]y=tan(u)

By the chain rule: d/dx[y(u)]=y'(u)*u'

y'=sec^2(color(red)u)

color(red)(u'=1/(1-3x)*-3=-3/(1-3x)

:.d/dx[y(u)]=sec^2(color(red)(ln(1-3x)))*color(red)(-3/(1-3x))=(-3sec^2(ln(1-3x)))/(1-3x)