What is the total differential of #z=x^2+2y^2-2xy+2x-4y-8#? Calculus Derivatives Differentiable vs. Non-differentiable Functions 1 Answer Jim H Mar 27, 2015 #delz = (del z)/ (del x) dx+ (del z)/ (del y) dy#, so #delz = (2x-2y+2) dx+ (4y-2x-4) dy# Answer link Related questions What are non differentiable points for a function? What does differentiable mean for a function? What are non differentiable points for a graph? How do you find the non differentiable points for a function? How do you find the non differentiable points for a graph? What are differentiable points for a function? How do you find the differentiable points for a graph? What is the derivative of a unit vector? On what interval is the function #ln((4x^2)+9)# differentiable? How do you find the partial derivative of the function #f(x,y)=intcos(-7t^2-6t-1)dt#? See all questions in Differentiable vs. Non-differentiable Functions Impact of this question 7362 views around the world You can reuse this answer Creative Commons License