Q. Given the function f(x)=(−10−2x2+5x−1)(−8−x2), find f′(x) in any form.Answer: f′(x)=
Apply Product Rule: To find the derivative of the function f(x)=(−10−2x2+5x−1)(−8−x2), 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.
Define Functions: Let's denote the first function as u(x)=−10−2x2+5x−1 and the second function as v(x)=−8−x2. We will first find the derivative of u(x), which is u′(x).
Find u′(x): The derivative of u(x)=−10−2x2+5x−1 is found by differentiating each term separately. The derivative of a constant is 0, the derivative of −2x2 is −4x, and the derivative of 5x−1 is −5x−2 (using the power rule).So, u′(x)=0−4x−5x−2.
Find v′(x): Now we will find the derivative of v(x)=−8−x2. The derivative of a constant is 0, and the derivative of −x2 is −2x. So, v′(x)=0−2x=−2x.
Use Product Rule: Using the product rule, the derivative of f(x) is f′(x)=u′(x)v(x)+u(x)v′(x). Substituting the derivatives we found, we get f′(x)=(−4x−5x−2)(−8−x2)+(−10−2x2+5x−1)(−2x).
Expand Expressions: Now we will expand the expressions to simplify them. For the first part, we distribute (−4x−5x−2) across (−8−x2), and for the second part, we distribute (−10−2x2+5x−1) across (−2x).
Expand First Part: Expanding the first part, we get:(−4x)(−8)+(−4x)(−x2)+(−5x−2)(−8)+(−5x−2)(−x2)=32x+4x3+40x−2+5x−2+2=32x+4x3+40x−2+5
Expand Second Part: Expanding the second part, we get:(−10)(−2x)+(−2x2)(−2x)+(5x−1)(−2x)=20x−4x3−10
Combine Like Terms: Now we combine like terms from both expanded parts to get the final derivative:f′(x)=(32x+4x3+40x−2+5)+(20x−4x3−10)=32x+4x3+40x−2+5+20x−4x3−10=52x+40x−2−5
Final Derivative: We have found the derivative of the function f(x), which is:f′(x)=52x+40x−2−5This is the final answer.
More problems from Find derivatives of using multiple formulae