A bead moves on a circular wire x^2 + y^2 = 25. As it passes the point (3,4), the x-coordinate is decreasing at a rate of 2 units per second. At what rate is the y changing?
plug and chug
x^2+y^2 = 25
2x dx/dt + 2y dy/dt = 0
Now you have x, y, dx/dt, so find dy/dt