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About 400,000 people visited an art museum in december. what could be the exact number of people who visited the art museum?

Convert the cartesian equation (x 2 + y 2)2 = 4(x 2 - y 2) to a polar equation. choices: r4 = -4r2 r2 = 4cos2θ r2 = 4sin2θ

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882