Q. Given the function f(x)=(−5−4x−2)(x2+6+6x), find f′(x) in any form.Answer: f′(x)=
Product Rule Application: To find the derivative of the function f(x)=(−5−4x−2)(x2+6+6x), we will use the product 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)=−5−4x−2 and v(x)=x2+6+6x. We will first find the derivative of u(x) with respect to x. The derivative of a constant is 0, and the derivative of −4x−2 is 8x−3 using the power rule, which states that (d/dx)(xn)=nxn−1. So, (d/dx)(u(x))=(d/dx)(−5)+(d/dx)(−4x−2)=0+8x−3.
Derivative of v(x): Next, we will find the derivative of v(x) with respect to x. The derivative of x2 is 2x, the derivative of 6 is 0, and the derivative of 6x is 6 using the power rule and the fact that the derivative of a constant is 0. So, v(x)0.
Applying Product Rule to Find f′(x): Now we can apply the product rule to find f′(x). f′(x)=u′(x)v(x)+u(x)v′(x) f′(x)=(8x−3)(x2+6+6x)+(−5−4x−2)(2x+6).
Simplifying f′(x) Expression: We will now simplify the expression for f′(x). First, distribute 8x−3 across (x2+6+6x): 8x−3x2+8x−36+8x−36x=8x−1+48x−3+48x−2.
Simplifying f′(x) Expression: We will now simplify the expression for f′(x). First, distribute 8x−3 across (x2+6+6x): 8x−3x2+8x−36+8x−36x=8x−1+48x−3+48x−2.Next, distribute (−5−4x−2) across (2x+6): −5(2x)−5(6)−4x−2(2x)−4x−2(6)=−10x−30−8x−1−24x−2.
Simplifying f′(x) Expression: We will now simplify the expression for f′(x). First, distribute 8x−3 across (x2+6+6x): 8x−3x2+8x−36+8x−36x=8x−1+48x−3+48x−2.Next, distribute (−5−4x−2) across (2x+6): −5(2x)−5(6)−4x−2(2x)−4x−2(6)=−10x−30−8x−1−24x−2.Now we combine like terms to get the final expression for f′(x): f′(x)=8x−1+48x−3+48x−2−10x−30−8x−1−24x−2. f′(x)0.
More problems from Find derivatives of using multiple formulae