Determine all points of intersection: y=cosx and y=sinx in the first quadrant

(note i put the graph in so plz )the graph shows the amount of water that remains in a barrel after it begins to leak. the variable x represents the number of days that have passed since the barrel was filled, and y represents the number of gallons of water that remain in the barrel. what is the slope of the line

I'll give brainliest if you answer right : )

What are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2