Ploting two function on one graph and using text() to place an arrow everywhere the lines intersect.

Hi, I have two functions F and f(x). One is a sin wave and the other a straight line. I need to use the text() function to place an arrow everywhere the lines intersect. How do I do this.

I know how to use Text() text(x,y,'\leftarrow')

Not sure how to input my x,y value when the intersection point depends on the user entering any number for F.