Apply Product Rule: Apply the product rule to find the derivative of f(x)=−2xcos(x).The product rule states that if you have a function that is the product of two functions, u(x) and v(x), then the derivative of this function is given by u′(x)v(x)+u(x)v′(x). Here, u(x)=−2x and v(x)=cos(x).
Differentiate −2x: Differentiate u(x)=−2x with respect to x. The derivative of −2x with respect to x is −2, since the derivative of x is 1.
Differentiate cos(x): Differentiate v(x)=cos(x) with respect to x. The derivative of cos(x) with respect to x is −sin(x).
Apply Product Rule: Apply the product rule using the derivatives from Step 2 and Step 3.Using the product rule, we have:f′(x)=u′(x)v(x)+u(x)v′(x)f′(x)=(−2)⋅cos(x)+(−2x)⋅(−sin(x))
Simplify Derivative: Simplify the expression for the derivative. f′(x)=−2cos(x)+2xsin(x)
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