Thread: Derivatives of inverse trig function

I need help taking the derivative of y = arctan(x+1)
This is what I do
y = arctan(x+1)
x=tan(y+1)
cos^2(y+1) = y'
cos^2(arctan(x+1)+1) = y'
cos^2(((1-sec^2x)^0.5)+2))=y'

I am suppose to get a polynomial but I cannot take the derivative of it to get one. I just get stuck at the last step. Any help?

Originally Posted by Barthayn

I need help taking the derivative of y = arctan(x+1)
This is what I do
y = arctan(x+1)
x=tan(y+1)
cos^2(y+1) = y'
cos^2(arctan(x+1)+1) = y'
cos^2(((1-sec^2x)^0.5)+2))=y'

I am suppose to get a polynomial but I cannot take the derivative of it to get one. I just get stuck at the last step. Any help?

The tan and arctan functions don't work that way. You can only take the tangent of the whole expression







When you differentiate wrt x you should get: