A clock's minute hand has length 4 and its hour hand length 3.

What is the distance between the tips at the moment when it is increasing most rapidly?

ans : 5 (units)
sol: f=dist^2=25-24cosA
If distance increases most rapidly so does its square.
therefore we can differentiate f ( dist^2):
f'=24sinA
f''=-24cosA=0
cosA=0=====> A=90,270 DEGREES

Pythagoras he say: dist=5

ady

Posted by Ady TZIDON on 2004-02-27 18:38:23