Partial derivatives
Multivariable and vector calculus · Mathematics
Study notes
Q: Find fx and fy for f(x,y) = x^3 + 2x^2 y - y^3. fx: treat y as constant. Derivative: 3x^2 + 4xy - 0 = 3x^2 + 4xy. fy: treat x as constant. Derivative: 0 + 2x^2 - 3y^2 = 2x^2 - 3y^2.