Part A
we have that
Both students verify the identity properly
student A ----> expand the left side of the identity
student B ----> expand the right side of the identity
but the result is the same
both students proved that the given equation is an identity
Part B
Identities
[tex]\begin{gathered} sin^2x+cos^2x=1\text{ ----> identity N 1 in step 3} \\ cos^2x=1-sin^2x \end{gathered}[/tex]
and
[tex]cscx=\frac{1}{sinx}\text{ -----> identity N 2 step 5}[/tex]
