# The derivative of the sine function

- Author:
- Daryl Funk

- Topic:
- Calculus, Derivative, Sine

Move the slider or input values for

*a*. The blue curve is the graph of*y=sin(x)*, and the red line is the tangent to the curve at the point*(a, sin(a))*. Recall that the slope of the tangent line to the curve at*(a,f(a))*is the value*f'(a)*. The red point is the point*(a, f'(a))*. Notice that the graph of*y=d/dx(sin(x))*is*cos(x)*.