Inverse Trig (1 Viewer)

[steve001]

Hey,
Im just a little confused about this question.
Find the equation of the tangent to y = tan^-1(ax+b) at the point where it crosses the x axis.
Thanks in advance

 

[kaz1]

Find the x intercept, sub that in the derivative to find the gradient of the tangent.

 

[shaon0]

Hey,
Im just a little confused about this question.
Find the equation of the tangent to y = tan^-1(ax+b) at the point where it crosses the x axis.
Thanks in advance

At y=0, x=(-b/a):
y'=a/((ax+b)^2+1)
At (0,(-b/a)):
y'=a
Equ of tangent:
y=a(x+(b/a))
y=ax+b