Rewrite function: We need to find the derivative of the function f(x)=x3 with respect to x. The function can be rewritten as f(x)=(x3)21.
Apply chain rule: To differentiate f(x)=(x3)21, we will use the chain rule. The chain rule states that the derivative of a composite function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function.
Find outer function derivative: The outer function is g(u)=u21 and the inner function is u(x)=x3. We will first find the derivative of the outer function, g′(u)=(21)u−21.
Find inner function derivative: Next, we find the derivative of the inner function, u′(x)=3x2.
Apply chain rule again: Now we apply the chain rule: f′(x)=g′(u(x))⋅u′(x). Substituting the derivatives we found, we get f′(x)=(21)(x3)−21⋅3x2.
Simplify expression: Simplify the expression: f′(x)=(23)x2⋅(x3)−21.
Rewrite with single exponent: Rewrite the expression with a single exponent: f′(x)=(23)x2−23=(23)x21.
Evaluate derivative at x=25: Now we evaluate the derivative at x=25: f′(25)=(23)(25)21.
Calculate final value: Since the square root of 25 is 5, we have f′(25)=(23)×5.
Calculate final value: Since the square root of 25 is 5, we have f′(25)=(23)×5.Finally, we calculate the value: f′(25)=(23)×5=215=7.5.
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