How do you find the derivative for #f(x)=sinxcosx#? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer GiĆ³ Mar 28, 2015 You can use the Product Rule: if: #k(x)=f(x)g(x)# #k'(x)=f'(x)g(x)+f(x)g'(x)# In your case: #f'(x)=cos(x)cos(x)+sin(x)(-sin(x))=# #=cos^2(x)-sin^2(x)=cos(2x)# Answer link Related questions What is the derivative of #y=cos(x)# ? What is the derivative of #y=tan(x)# ? How do you find the 108th derivative of #y=cos(x)# ? How do you find the derivative of #y=cos(x)# from first principle? How do you find the derivative of #y=cos(x^2)# ? How do you find the derivative of #y=e^x cos(x)# ? How do you find the derivative of #y=x^cos(x)#? How do you find the second derivative of #y=cos(x^2)# ? How do you find the 50th derivative of #y=cos(x)# ? How do you find the derivative of #y=cos(x^2)# ? See all questions in Derivative Rules for y=cos(x) and y=tan(x) Impact of this question 13699 views around the world You can reuse this answer Creative Commons License