Hello, I have real analysis questions.

I need your help.

Thank you so much.

\fQuestion 5.106. Argue f(;17, y. z) = I2 + $3] + :2 cos y has a critical point at the origin. VVl'lat type of critical point? Question 5.100. Consider y as implicitly defined as a function of x via the equa- tion 2 2 + y' tell = 0 Compute y'(x) in terms of x and y.Optimization, Lagrange Question 5.104. Use the completing squares technique to find the sigature of the quadratic forms below. (1) x2 +xy - 342 (2) x2 + 2xy - 92 (3) x2 + xy + yz