AP Calculus
posted by Jeff .
A particle is moving around the unit circle (the circle of radius 1 centered at the origin). At the point (.6, .8) the particle has horizontal velocity dx/dt=3. what is its vertical velocity dy/dt at that point?
a)3.875
b03.75
c)2.25
d03.75
e)3.875

x^2 + y^2 = 1
2x dx/dt + 2y dy/dt = 0
dy/dt = (x dx/dt)/y
= .6(3)/.8 =  2.25