calculus IIInote : number 2. show that the function f(x,y) .....

Determine the limit value of: (If there is) Lim 2xy (x, y) - (0,0) x2 + y2 Show that the function f (x, y) = 3x+4y continuous at point (1,1) xty+1 Find the first partial derivative of Z = cos (2x) - x2e5y + 3y2 to x and against y. Find all the second partial derivatives of f(x, y) = x2 + In(5x - 3y2)