Product Rule Explanation: To find the derivative of f(x)=−4x(3x4), we will use the product rule and the chain rule. The product rule states that the derivative of a product of two functions is the derivative of the first function times the second function plus the first function times the derivative of the second function.
Derivative of u(x): Let's denote the two functions as u(x)=−4x and v(x)=3(x4). We will find the derivatives of u(x) and v(x) separately.
Derivative of v(x): The derivative of u(x)=−4x with respect to x is u′(x)=−4, since the derivative of x with respect to x is 1.
Chain Rule Application: To find the derivative of v(x)=3x4, 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.
Derivative of v(x): The outer function is g(y)=3y, and the inner function is h(x)=x4. The derivative of the outer function with respect to y is g′(y)=3y⋅ln(3), and the derivative of the inner function with respect to x is h′(x)=4x3.
Product Rule Application: Applying the chain rule, the derivative of v(x) is v′(x)=g′(h(x))⋅h′(x)=3(x4)⋅ln(3)⋅4x3.
Simplify Expression: Now we can apply the product rule to find the derivative of f(x)=u(x)v(x). Using the product rule, f′(x)=u′(x)v(x)+u(x)v′(x).
Factor Out Common Term: Substituting the derivatives we found, f′(x)=(−4)(3x4)+(−4x)(3x4⋅ln(3)⋅4x3).
Factor Out Common Term: Substituting the derivatives we found, f′(x)=(−4)(3x4)+(−4x)(3x4⋅ln(3)⋅4x3). Simplify the expression to combine like terms. f′(x)=−4⋅3x4−16x4⋅3x4⋅ln(3).
Factor Out Common Term: Substituting the derivatives we found, f′(x)=(−4)(3x4)+(−4x)(3x4⋅ln(3)⋅4x3). Simplify the expression to combine like terms. f′(x)=−4⋅3x4−16x4⋅3x4⋅ln(3). Factor out the common term 3x4 to get the final derivative. f′(x)=3x4⋅(−4−16x4⋅ln(3)).
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