Menu Close

f-x-y-x-y-2-x-2-y-2-f-u-f-v-x-uv-y-u-v-




Question Number 424 by 123456 last updated on 25/Jan/15
f(x,y)=(((x+y)^2 )/(x^2 +y^2 ))   { (((∂f/∂u)=?)),(((∂f/∂v)=?)) :}   { ((x=uv)),((y=u+v)) :}
f(x,y)=(x+y)2x2+y2{fu=?fv=?{x=uvy=u+v
Answered by prakash jain last updated on 02/Jan/15
f(u,v)=1+((2xy)/(x^2 +y^2  )) = 1+((2u^2 v+2uv^2 )/((uv)^2 +(u+v)^2 ))  (∂f/∂u)=(([(uv)^2 +(u+v)^2 ][4uv+2v^2 ]−(2u^2 v+2uv^2 )(2uv+2u+2v))/([(uv)^2 +(u+v)^2 ]^2 ))  Simplification  4u^3 v^3 +4u^3 v+8u^2 v^2 +4uv^3 +2u^2 v^4 +2u^2 v^2 +4uv^3 +2v^4   −4u^3 v^2 −4u^2 v^3 −4u^3 v−4u^2 v^2 −4u^2 v^2 −4uv^3   =4u^3 v^3 +2u^2 v^4 +2u^2 v^2 +4uv^3 +2v^4 −4u^3 v^2 −4u^2 v^3   (∂f/∂u)=((4u^3 v^3 +2u^2 v^4 +2u^2 v^2 +4uv^3 +2v^4 −4u^3 v^2 −4u^2 v^3 )/([(uv)^2 +(u+v)^2 ]^2 ))  (∂f/∂v)=((4u^3 v^3 +2v^2 u^4 +2u^2 v^2 +4vu^3 +2u^4 −4v^3 u^2 −4v^2 u^3 )/([(uv)^2 +(u+v)^2 ]^2 ))
f(u,v)=1+2xyx2+y2=1+2u2v+2uv2(uv)2+(u+v)2fu=[(uv)2+(u+v)2][4uv+2v2](2u2v+2uv2)(2uv+2u+2v)[(uv)2+(u+v)2]2Simplification4u3v3+4u3v+8u2v2+4uv3+2u2v4+2u2v2+4uv3+2v44u3v24u2v34u3v4u2v24u2v24uv3=4u3v3+2u2v4+2u2v2+4uv3+2v44u3v24u2v3fu=4u3v3+2u2v4+2u2v2+4uv3+2v44u3v24u2v3[(uv)2+(u+v)2]2fv=4u3v3+2v2u4+2u2v2+4vu3+2u44v3u24v2u3[(uv)2+(u+v)2]2