Use the chain rule to find the indicated partial derivatives. W = xy yz zx, x = r cos(������), y = r sin(������), z = r������; ∂w ∂r , ∂w ∂������ when r = 2, ������ = ������ 2.

ind the center and radius of the sphere: x2 + y2 +z2-8x + 2y + 62+1 0 2) Find an equation of the sphere that passes through the point (6,-2, 3) and has center (-1,2, 1). Find the curve in which the sphere from #2 intersects the yz-plane. For #4-11, u : ? + j-2k 4) 2u +3v 5) Iv 6) uv and v-3i-2j + k 8) Ivxu 9) comp,v 10) proju 11) Find the angle between u and v 12) Find the scalar triple product of a, b, and c. If a (3, 1,2), b (-1,1,0), and c (0,0,-4) 13) Find the values of x such that (3,2, x) and (2x, 4, x) are orthogonal 14) Find two unit vectors that are orthogonal to both j + 2k and i-2j+3k 15) Find the acute angle between two diagonals of a cube 16) Find a vector perpendicular to the plane through the points A(1,0,0), B(2,0,-1) and C(1,4,3) 17) Find parametric equations for the line through (4,-1, 2) and (1, 1, 5) 18) Find parametric equations for the line through (-2, 2, 4) and perpendicular to the plane 2x-y+5z 12 19) Find an equation of the plane through (2, 1,0) and parallel to x + 4y -3z 1 20) Find an equation of the plane through (3, -1, 1), (4, 0, 2), and (6, 3, 1). 21) Show that the planes x y-z 1 and 2x 3y + 4z 5 are neither parallel nor perpendicular. Find the angle between the planes.