Identify Functions: We need to find the derivative of the function y=tan−1(8x+91). To do this, we will use the chain rule, which 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 Outer Function: First, let's identify the outer function and the inner function. The outer function is tan−1(u), where u is the inner function. The inner function is 8x+91.
Derivative of Inner Function: The derivative of the outer function tan−1(u) with respect to u is 1+u21. We will apply this after we find the derivative of the inner function.
Apply Chain Rule: The derivative of the inner function 8x+91 with respect to x is found using the quotient rule or recognizing it as (8x+9)−1 and using the power rule. The derivative is −(8x+9)28.
Simplify Expression: Now we apply the chain rule. The derivative of y with respect to x is the derivative of the outer function evaluated at the inner function times the derivative of the inner function. This gives us:dxd[tan−1(8x+91)]=1+(8x+91)21⋅(−(8x+9)28).
Final Derivative: Simplify the expression. The (8x+9)2 in the denominator of the derivative of the inner function cancels with the (8x+9)2 in the 1+(8x+91)2 term, leaving us with:dxd[tan−1(8x+91)]=−1+(8x+9)28.
Final Derivative: Simplify the expression. The (8x+9)2 in the denominator of the derivative of the inner function cancels with the (8x+9)2 in the 1+(8x+91)2 term, leaving us with:dxd[tan−1(8x+91)]=−1+(8x+9)28.The final simplified form of the derivative is:dxd[tan−1(8x+91)]=−1+64x2+144x+818.