1. You asked for help with multivariable calculus questions step by step. 2. Please provide the specific multivariable calculus problem you want to solve. 3. Once you provide the problem, I will explain the relevant formulas, rules, and solve it with detailed steps. 4. Multivariable calculus typically involves functions of several variables, partial derivatives, gradients, multiple integrals, and more. 5. To proceed, please share the first problem you want to work on.