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TEST TOMMOROW PLEASE SHOW YOUR WORK AND AVOID SPHERICAL COORDINATES IF POSSIBLE

ID: 3194045 • Letter: T

Question

TEST TOMMOROW PLEASE SHOW YOUR WORK AND AVOID SPHERICAL COORDINATES IF POSSIBLE

Will give lifesaver to most accurate answer as I need to be able to understand how to do these flux integrals for my exam.

Explanation / Answer

Let f(x, y, z) = x² z + y² z ?? f(x, y, z) dS = ?? f(r(u,v)) * ||r? x r?|| dA ? . . . . . . . . . . . . ? where r(u,v) = is parameterization of S. Parameterization of sphere is given by: r(?,f) = < ? sinf cos?, ? sinf sin?, ? cosf > r? = < -? sinf sin?, ? sinf cos?, 0 > r? = < ? cosf cos?, ? cosf sin?, -? sinf > r? x r? = < -?² sin²f cos?, -?² sin²f sin?, -?² sinf cosf sin²? - ?² sinf cosf cos²? > r? x r? = < -?² sin²f cos?, -?² sin²f sin?, -?² sinf cosf > ||r? x r?||² = ?4 sin4f cos²? + ?4 sin4f sin²? + ?4 sin²f cos²f . . . . . . . . = ?4 sin4f (cos²? + sin²?) + ?4 sin²f cos²f . . . . . . . . = ?4 sin4f + ?4 sin²f cos²f . . . . . . . . = ?4 sin²f (sin²f + cos²f) . . . . . . . . = ?4 sin²f ||r? x r?|| = ?² sinf Since we are working on the upper half of a sphere with radius ? = 2, then we get ||r? x r?|| = 4 sinf and limits are 0 = ? = 2p and 0 = f = p/2 f(x, y, z) = x² z + y² z f(r(?,f)) = f(2 sinf cos?, 2 sinf sin?, 2 cosf) . . . . . . . = 8 sin²(f) cos²(?) cos(f) + 8 sin²(f) sin²(?) cos(f) . . . . . . . = 8 sin²(f) cos(f) (cos²(?) + sin²(?)) . . . . . . . = 8 sin²(f) cos(f) ?? f(x, y, z) dS = ?? f(r(?,f)) * ||r? x r?|| dA ?? (x² z + y² z) dS = ?0²???0??/² (8 sin²(f) cos(f) * 4 sinf) dfd? = ?0²???0??/² (32 sin³(f) cos(f)) dfd? = ?0²?? (8 sin4(f) |0??/²) d? = ?0²?? (8 (sin4(p/2) - sin4(0))) d? = ?0²?? (8 (1 - 0) d? = ?0²?? 8 d? = 8? |0²?? = 16p