vikash chandola
Last Activity: 14 Years ago
Hello baha
The rate of change of a function means its derivative so when you talk about rate of change of f(x) it is f ‘(x) and the rate of change of g(x) is g ‘(x) according to question rate of change of both function is equal means f ‘(x) =g’(x)
f ’(x) = -cos(x)/((sinx)*(sinx)) and g’(x)=sin(x)/((cosx)*(cosx))
f ‘(x)=g’(x)
-cos(x)/((sinx)*(sinx))= sin(x) /((cosx)*(cosx))
-(cos(x)) ^3 = (sin(x))^3
This implies that
-cos(x)= sin(x)
Hence x belongs to (pi/2,pi)union(-pi/2,0)