For some reason I keep getting Part C wrong but im using the right formula Please help!! Learning Goal:

To determine the internal moments within a cantilever beam that has two different cross$-$sectional areas and two externally applied moments acting on it$,$ and to determine the radius of curvature for each section of the beam.

The cantilever beam ABC $($Figure $1)$shown is composed of two solid cylindrical sections: AB has a diameter of d$1$

$=2\mathrm{.}00$ in

and BC has a diameter of d$2$

$=7\mathrm{.}00$ in

$.$ The two moments, MA

$=60\mathrm{.}0$ kip$$ft

and MB

$=56\mathrm{.}0$ kip$$ft

$,$ are applied externally at points A and B$,$ respectively. Assume EI

is constant with E$=2\mathrm{.}8\backslash$times $107$psi

and that a

$=1\mathrm{.}50$ ft

and b

$=1\mathrm{.}00$ ft