Given x^t * y^m - (x+y)^(m+t)=0xtym(x+y)m+t=0 determine dy/dxdydx ?

1 Answer
Oct 28, 2016

See below.

Explanation:

f(x,y)=x^t * y^m - (x+y)^(m+t)=0f(x,y)=xtym(x+y)m+t=0

df = f_xdx+f_ydy=0df=fxdx+fydy=0 so

dy/dx=-f_x/(f_y)dydx=fxfy but

f_x=t/x x^ty^m-(t+m)/(x+y)(x+y)^(t+m)fx=txxtymt+mx+y(x+y)t+m

and

f_y=m/y x^ty^m-(t+m)/(x+y)(x+y)^(t+m)fy=myxtymt+mx+y(x+y)t+m

but

x^ty^m=(x+y)^(t+m)xtym=(x+y)t+m then

f_x=(t/x-(t+m)/(x+y))x^ty^mfx=(txt+mx+y)xtym and
f_y=(m/y-(t+m)/(x+y))x^ty^mfy=(myt+mx+y)xtym

so

dy/dx=-(t/x - (t + m)/(x + y))/(m/y - (t + m)/(x + y))=y/xdydx=txt+mx+ymyt+mx+y=yx