Darryl B. answered 10/26/20
Tutor
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IVY Quantum Theorist for Online Math and Physics Tutorials
Hi Bella, The problem asks us to evaluate
csc((3pi)/2-t)
which is equal to
1/sin((3pi)/2-t).
In order to simplify, we need to use the differences formula for cosine:
sin(A-B)=sinAcosB-cosAsinB.
The denominator, therefore, is equal to
sin((3pi)/2-t)=(sin((3pi)/2)cost-cos((3pi)/2)sin(t)
but cos((3pi)/2)=0 and sin((3pi)/2)=-1, so
(sin((3pi)/2)cost-cos((3pi)/2)sin(t)=(-1)(cost)-(0)(sint)=-cost.
Therefore, csc((3pi)/2-t)=1/sin((3pi)/2-t)=1/(-cost)=-sect.
I hope this helps!