Define:
d/dx(f(x)) = f'(x)
where f'(x) = gradient (or slope) of f(x) at x = x.
Prove that:
d/dx(x^2) = 2x
without using calculus.
(In reply to
re(5): Hmmmm by friedlinguini)
"Define f(x) = x². Define f'(x) as the slope of the curve generated by f(x) for any given value of x. Prove that f'(x) = 2x."
i agree, that sounds like a good formulation. levik, feel free
to change it to this if you think this is clearer. (adding the
dont use calculus bit)
here's another hint:
tangents and circles