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Find f(x)f'(x) where f(x)=2xcos(x)f(x)=-2x\cos(x)

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Q. Find f(x)f'(x) where f(x)=2xcos(x)f(x)=-2x\cos(x)
  1. Apply Product Rule: Apply the product rule to find the derivative of f(x)=2xcos(x)f(x)=-2x \cos(x).\newlineThe product rule states that if you have a function that is the product of two functions, u(x)u(x) and v(x)v(x), then the derivative of this function is given by u(x)v(x)+u(x)v(x)u'(x)v(x) + u(x)v'(x). Here, u(x)=2xu(x) = -2x and v(x)=cos(x)v(x) = \cos(x).
  2. Differentiate 2x-2x: Differentiate u(x)=2xu(x) = -2x with respect to xx. The derivative of 2x-2x with respect to xx is 2-2, since the derivative of xx is 11.
  3. Differentiate cos(x)\cos(x): Differentiate v(x)=cos(x)v(x) = \cos(x) with respect to xx. The derivative of cos(x)\cos(x) with respect to xx is sin(x)-\sin(x).
  4. Apply Product Rule: Apply the product rule using the derivatives from Step 22 and Step 33.\newlineUsing the product rule, we have:\newlinef(x)=u(x)v(x)+u(x)v(x)f'(x) = u'(x)v(x) + u(x)v'(x)\newlinef(x)=(2)cos(x)+(2x)(sin(x))f'(x) = (-2) \cdot \cos(x) + (-2x) \cdot (-\sin(x))
  5. Simplify Derivative: Simplify the expression for the derivative. f(x)=2cos(x)+2xsin(x)f'(x) = -2\cos(x) + 2x\sin(x)

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