Q. Given the function y=−3(4x2−9x)4, find dxdy in any form.Answer: dxdy=
Apply Chain Rule: To find the derivative of the function y=−3(4x2−9x)4 with respect to x, 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.
Identify Outer and Inner Functions: First, let's identify the outer function and the inner function. The outer function is u4 (where u is a function of x), and the inner function is u=4x2−9x. We will need to take the derivative of the outer function with respect to u and then multiply it by the derivative of the inner function with respect to x.
Derivative of Outer Function: The derivative of the outer function u4 with respect to u is 4u3. So, if we apply this to our function, we get the derivative of −3(4x2−9x)4 with respect to the inner function (4x2−9x) as −3×4(4x2−9x)3.
Derivative of Inner Function: Now, we need to find the derivative of the inner function 4x2−9x with respect to x. The derivative of 4x2 with respect to x is 8x, and the derivative of −9x with respect to x is −9. So, the derivative of the inner function with respect to x is 8x−9.
Combine Derivatives: We can now combine the derivatives of the outer and inner functions. The derivative of y with respect to x is the derivative of the outer function times the derivative of the inner function, which is −3×4(4x2−9x)3×(8x−9).
Simplify Expression: Simplify the expression by multiplying the constants and combining like terms. The derivative of y with respect to x is −12(4x2−9x)3⋅(8x−9).
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