Which sentence is true iready math

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

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Find the missing dimension! need asap! tiny square is a =3025 in ²