Find the Derivative f(x)=x-2cos(x)

Differentiate.
By the Sum Rule, the derivative of with respect to is .
Differentiate using the Power Rule which states that is where .
Evaluate .
Since is constant with respect to , the derivative of with respect to is .
The derivative of with respect to is .
Multiply by .
Find the Derivative f(x)=x-2cos(x)