Which of the following differential equations M(x,y) dx+N(x,y) dy=0M(x,y)\,dx + N(x,y)\,dy = 0M(x,y)dx+N(x,y)dy=0 is NOT exact?
(x2+2xy) dx+(x2+y) dy=0(x^2 + 2xy)\,dx + (x^2 + y)\,dy = 0(x2+2xy)dx+(x2+y)dy=0
(y+x) dx+(x+2y) dy=0(y + x)\,dx + (x + 2y)\,dy = 0(y+x)dx+(x+2y)dy=0
(2xy+1) dx+(x2y+y) dy=0(2xy + 1)\,dx + (x^2y + y)\,dy = 0(2xy+1)dx+(x2y+y)dy=0
(yexy+2x) dx+(xexy−1) dy=0(ye^{xy} + 2x)\,dx + (xe^{xy} - 1)\,dy = 0(yexy+2x)dx+(xexy−1)dy=0