Moment of inertia of thin-walled sections body structure typically consists of beams with thin-walled sections in which the width-to-thickness ratio, b/t, is large (b/t > 60). a) write an expression for the exact area moment of inertia about the x axis, ixx. b) whent is very small compared to the other section dimensions, we can approximate the exact ixx with an expression linear in t. using either a taylor expansion of part a or by elimination of terms of t of second and higher order, write the linear approximation for ixx. c) for b=50 mm, h=100 mm, and 5