35 1. A thin metal plate, located in the planexy, it has temperatureI (x, y)on the point(x,y). Draw, in detail, isothermal curves if (x, y) = 1+2+2. The following table presents the numerical values for two different functions. Explain in detail the behavior of both functions near the origin, and where they tend as they approach the origin. 3. Find and draw the domain of the functionf(x, y) = x sec y. 4. Find the limit (if it exists) off(x, y) = according to(x, y) 0. If the limit does not exist, explain why.