Find the derivative of the function. Simplify where possible.
arctan(x - sqrt(1+x2))
The Attempt at a Solution
let u = x - sqrt(1+x2)
y = tan-1(u)
dy/du = 1/(1+ u2)
sub in u.
dy/du = 1/1 + (x - sqrt(1+x2))2
du/dx = 1 - 1/2 (1+x2)-1/2 (2x)
dy/dx = (1/1 + (x - sqrt(1+x2))2) (1 - 1/2 (1+x2)-1/2 (2x))
I always seem to forget 1 term and I am basically wondering if my method here is correct.