11. (a) Find the area of the region enclosed by the curve \(y = x \sinh x\), the \(x\)-axis and the lines \(x = 0\) and \(x = 1\).
(b) The region \(R\) is bounded by the curve \(y = \cosh 2 x\), the \(x\)-axis and the lines \(x = 0\) and \(x = 1\). Find the volume of the solid generated when \(R\) is rotated through four right-angles about the \(x\)-axis.
(c) Using your answer to part (b), find the total volume of the solid generated by rotating the region bounded by the curve \(y = \cosh 2 x\) and the lines \(x = - 1\) and \(x = 1\).