Clac math
posted by Nikki .
a 20 foot ladder leaning up against a vertical wall begins to slip. the base of the ladder makes an acute angle with the floor. when the angle equals 60 degrees the angle is decreasing at 0.1 radians/second. find the rate at which the height of th upper end of the ladder is changing when the angle equals 60 dregrees

a = angle to floor = 60 at t
h = height = 20 sin a
dh/dt = 20 cos a da/dt
at a = 60 deg, cos a = 1/2 and da/dt=.1
dh/dt = 20 (1/2) (.1)
= 1 ft/s
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