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Multiple Choice
Differentiate the function: . Which of the following is the correct derivative ?
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Verified step by step guidance
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Step 1: Recognize that the function f(x) = x * cos(x) * sin(x) is a product of three functions: x, cos(x), and sin(x). To differentiate this, we will use the product rule multiple times.
Step 2: Recall the product rule: If u(x) and v(x) are functions, then the derivative of their product is given by (u * v)' = u' * v + u * v'.
Step 3: Apply the product rule to f(x). First, treat x as one function and cos(x) * sin(x) as another. Differentiate x to get 1, and leave cos(x) * sin(x) unchanged. Then, leave x unchanged and differentiate cos(x) * sin(x).
Step 4: To differentiate cos(x) * sin(x), use the product rule again. Let u(x) = cos(x) and v(x) = sin(x). Differentiate cos(x) to get -sin(x), and differentiate sin(x) to get cos(x). Combine these results: (cos(x) * sin(x))' = -sin^2(x) + cos^2(x).
Step 5: Substitute the results back into the original differentiation process. Combine terms carefully to arrive at the derivative f'(x) = cos(x) * sin(x) + x * [cos^2(x) - sin^2(x)].