Which one of the following equation is exact differential equation ) (y sin 2x)dx- (y? + cos? x)dy = 0 b) (y sin 2x)dx- (y? +x)dy = 0 dy 2x+ y+1 c) d) None of these %3D dx y +4x-3 Ob The implicit solution of the differential equation (1+x*)dy=(1+ y')dx by using variable separable method is tanx = tany -1 ) tany = tanx+c b) c) In (x + 1) = In y + In c d) None of these