Use stokes' theorem to change ∫∫∇×⋅∫∫s∇×f⋅nds to an equivalent surface integral and evaluate it, where =++=xi+y2j+xyzk, is the upward unit normal, and is the part of the paraboloid z=4−x2−y2z=4−x2−y2 with z≥0z≥0.

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations