find the total differential: u=sqrt(x^2+3y^2)

Answer 1

du = du/dx * dx + du/dy * dy
u= (x^2+3y^2)^0.5
du = .5 (x^2+3y^2)^-.5 * 2 x dx + .5 (x^2+3y^2)^-.5 * 6 y dy
du = [ x dx + 3 y dy ] / sqrt(x^2+3y^2)