xy2-x+2x2 +jz 5 Given temperature T(x,y,z)= a) Find an equation of the tangent plane and normal line TO THE LEVEL SURFACE of T passing through the point P (1,2,1) b) Find the rate of change of T.yz) at P in the direction PQ where Q- (1,2,3) c) in which direction T increases (decreases) most rapidly? 5. Given z= (4). +7)e-r-) a) Find (and classify) all critical points of z which are INSIDE the domain (Use 2-d Derivative Test), b)Use the method of Lagrange multipliers to find MAX (MIN) values of z on the boundary of the domain. ),2-1 on the domainx +