Question

If x^2+y^2 =25 and dy/dt =6, find dx/dt when y=4

Answer 1

2x dx/dt +2y dy/dt =0
x dx/dt +y (6)=0
dx/dt= -6y/x
dx/dt= -6*4 /x
dx/dt=-24/x
also from the given equation x^2= 25-16=9 or x=3
using this we get
dx/dt=-24/3 =-8