1. The problem statement, all variables and given/known data Given f(x) = x^(2/3), find f'(x) using the Δ method. 2. Relevant equations f'(x) = (f(x + Δx) – f(x))/(Δx) 3. The attempt at a solution I understand the entire solution (that is attached along with the problem as a png file), except how to get [(x + Δx)^(4/3) + (x + Δx)^(2/3) x^(2/3) + x^(4/3)]/[(x + Δx)^(4/3) + (x + Δx)^(2/3) x^(2/3) + x^(4/3)] = 1, without looking at the solution. How would I come up with that on my own? What's “playing tricks with my head” is the fractional exponents. If it were dealing with square roots, for example, I would simply multiply the numerator and denominator by the conjugate of the numerator. Any input would be GREATLY appreciated!