# Vol of revolution(1 line and 1 function)

Calculus Level pending

Find the volume of the solid of revolution formed by revolving the region bounded by $$f(x)=x+4$$ and the $$x$$-axis ($$2\leq x\leq4$$) about $$y$$- axis. If your answer is $$\dfrac ab \pi$$*21/64, where $$a$$ and $$b$$ are coprime positive integers, find $$a+b$$.

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