Solve example on various calculators

[Albert Chan]

Cas> zeros((x+1) * sqrt(x*x-2*x-1))

[-1, √2+1, -√2+1]

By hand:

f = (x+1) * sqrt(x*x-2*x-1)
ln(f) = ln(x+1) + 1/2 * ln(x*x-2*x-1)
f'/f   = 1/(x+1) + (x-1)/(x*x-2*x-1) = 1/(x+1) + 1/((x-1) - 2/(x-1))

f'/f is rational polynomial, without sqrt.

f = 0      → f'/f = ±∞      → x = -1, 1±√2