Q. Find the derivative of the following function.y=log8(7x5−8x4)Answer: y′=
Apply Change of Base Formula: To find the derivative of the function y=log8(7x5−8x4), we will use the change of base formula for logarithms and the chain rule for differentiation.Change of base formula: logab=logcalogcbWe will use the natural logarithm (base e) for this purpose.y=log8(7x5−8x4) can be rewritten as y=ln(8)ln(7x5−8x4)
Use Chain Rule for Differentiation: Now we need to differentiate the function with respect to x using 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.Let u=7x5−8x4, then y=ln(8)ln(u)The derivative of ln(u) with respect to u is u1, and we need to multiply this by the derivative of u with respect to x.
Find Derivative of Inner Function: Let's find the derivative of u=7x5−8x4 with respect to x. Using the power rule, the derivative of xn with respect to x is n⋅x(n−1). The derivative of 7x5 is 35x4 and the derivative of −8x4 is −32x3. So, the derivative of u with respect to x is x1.
Apply Chain Rule to Find Derivative: Now we can apply the chain rule to find the derivative of y.y′=u1⋅dxdu/ln(8)Substitute u=7x5−8x4 and dxdu=35x4−32x3 into the equation.y′=(7x5−8x4)1⋅ln(8)(35x4−32x3)
Simplify the Derivative: Finally, we simplify the expression for the derivative.y′=(7x5−8x4)⋅ln(8)35x4−32x3This is the derivative of the function y=log8(7x5−8x4) with respect to x.
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