Teaching MPPSC Assistant Professor Mock Test Series 2025 Engineering Mathematics Differential Equations Partial Differential Equations
if \(u = {\tan ^{ - 1}}(\frac{{x + y}}{{\sqrt x + \sqrt y }})\) then \(x\frac{{\partial u}}{{\partial x}} + y\frac{{\partial u}}{{\partial y}}\) equals
1
2 cos 2u
2
(1/4) sin 2u
3
(1/4) tan u
4
2 tan 2u