How do you find the derivative of y = arctan(sqrt(3(x^2)-1))y=arctan(3(x2)1)?

1 Answer
Jun 18, 2017

dy/dx=1/(xsqrt(3x^2-1))dydx=1x3x21

Explanation:

The first thing to know is the derivative of the function y=tan^-1(u)y=tan1(u), where u=g(x)u=g(x) (think "the function on the inside").

d/dx(tan^-1(u))=1/(1+u^2) (du)/dxddx(tan1(u))=11+u2dudx

dy/dx=d/dx[tan^-1(sqrt(3x^2-1))]dydx=ddx[tan1(3x21)]

=1/(1+(sqrt(3x^2-1))^2) d/dx[(3x^2-1)^(1/2)]=11+(3x21)2ddx[(3x21)12]

=1/(1+3x^2-1) (1/2(3x^2-1)^(-1/2)(6x))=11+3x21(12(3x21)12(6x))

=1/(cancel(3)x^cancel(2)) (cancel(3)cancel(x)(3x^2-1)^(-1/2))

=1/(xsqrt(3x^2-1))