Find 
if 
Q20: Find the critical points of <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg"
Q21: Evaluate the limit or state that it
Q22: Let <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg" alt="Let Find
Q23: Find the tangent plane to the surface
Q24: The temperature at the point <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg"
Q26: Let <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg" alt="Let .
Q27: Find the global maximum of <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg"
Q28: Find the linearization of <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg" alt="Find
Q29: Let the functions <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg" alt="Let the
Q30: Let <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB5596/.jpg" alt="Let .