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Derivative of a fractional power function

Let f(x)=x0.75f(x) = x^{0.75}. Find f′(x)f'(x).

Hint

Apply the power rule ddx[xn]=nxn−1\frac{d}{dx}[x^n] = n x^{n-1} directly with n=0.75n = 0.75.

Step-by-step solution

Using the power rule, bring the exponent 0.750.75 down as a coefficient: f′(x)=0.75⋅x0.75−1f'(x) = 0.75 \cdot x^{0.75 - 1}.

Simplify the exponent: 0.75−1=−0.250.75 - 1 = -0.25, so f′(x)=0.75 x−0.25f'(x) = 0.75\, x^{-0.25}, which can also be written as 34 x0.25\dfrac{3}{4\,x^{0.25}}.

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