Strange problem with chain rule

**Paze** · February 24th 2013, 04:37 PM

derive x/(1-x^2) - Wolfram|Alpha

How on earth does 1-x^2 become x^2-1?!

Thanks.

**jakncoke** · February 24th 2013, 04:42 PM

$(1-x^2)^2 = x^4 - 2x^2 + 1$
$(x^2-1)^2 = x^4 - 2x^2 + 1$

This is because, for square functions f(-x) = f(x)

**Paze** · February 24th 2013, 04:44 PM

Originally Posted by jakncoke

$(1-x^2)^2 = x^4 - 2x^2 + 1$
$(x^2-1)^2 = x^4 - 2x^2 + 1$

Doh..I did suspect that, but I dismissed it as being too far out. Why go through the step of re-arranging it. Weird calculator.

Thread: Strange problem with chain rule