Q: Find d/dx f(x) if f(x)=3x^2.
A: Find d/dx is telling us to find the derivative, also known as f'(x).
f(x) = 3x^2
f'(x) = 2*3x = 6x.
How do I know this? The power rule. The power rule tells us to bring the power (or exponent) down in front as a multiplier, and subtract 1 from it:
f(x) = 3x^2 [bring the “2” down in front as a multiplier and subtract 1 from it]
f'(x) = 2 * 3x^(2-1) = 6x^1 = 6x.