Q. Find the derivative of the following function.y=log7(9x6)Answer: y′=
Understand function and derivative: Understand the function and the type of derivative to find.We need to find the derivative of the function y with respect to x, where y is a logarithm with base 7 of the function 9x6. We will use the chain rule and the formula for the derivative of a logarithm with an arbitrary base.
Apply chain rule and formula: Apply the chain rule and the logarithmic derivative formula. 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. The derivative of logb(u) with respect to u is u⋅ln(b)1, where b is the base of the logarithm and ln is the natural logarithm.
Calculate inner function derivative: Calculate the derivative of the inner function 9x6 with respect to x. The inner function is 9x6, and its derivative with respect to x is 54x5 (using the power rule: dxd[axn]=n⋅ax(n−1)).
Combine using chain rule: Combine the results using the chain rule.The derivative of y with respect to x is the derivative of the outer function (log7(u)) times the derivative of the inner function (9x6). Using the formula from Step 2 and the result from Step 3, we get:y′=9x6⋅ln(7)1⋅54x5
Simplify the expression: Simplify the expression.We can simplify the expression by canceling out an x5 from the numerator and denominator, and simplifying the constants:y′=9⋅ln(7)54⋅x5−6y′=ln(7)6⋅x−1y′=ln(7)6x−1
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