Apply Product Rule: We need to find the derivative of the function f(x)=sin(2x)cos(x). To do this, we will use the product rule, which 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)=sin(2x) and the second function as v(x)=cos(x). According to the product rule, the derivative of f(x) with respect to x is f′(x)=u′(x)v(x)+u(x)v′(x).
Find Derivative of u(x): Now we need to find the derivative of u(x)=sin(2x). The derivative of sin(2x) with respect to x is 2cos(2x), because the derivative of sin(ax) with respect to x is acos(ax), where a is a constant.
Find Derivative of v(x): Next, we need to find the derivative of v(x)=cos(x). The derivative of cos(x) with respect to x is −sin(x), because the derivative of cos(x) is −sin(x).
Apply Derivatives to Product Rule: Now we can apply the derivatives we found to the product rule. We have u′(x)=2cos(2x) and v′(x)=−sin(x). Plugging these into the product rule formula, we get f′(x)=(2cos(2x))(cos(x))+(sin(2x))(−sin(x)).
Simplify Expression: Simplify the expression for f′(x) by multiplying the terms. This gives us f′(x)=2cos(2x)cos(x)−sin(2x)sin(x).
Final Answer: The expression for f′(x) is now simplified, and we have found the derivative of the function f(x)=sin(2x)cos(x). The final answer is f′(x)=2cos(2x)cos(x)−sin(2x)sin(x).
More problems from Find limits involving trigonometric functions