csc(x+(3pi)/2)= -sec(x) How do I verify this?

[usines0820]

csc(x+(3pi)/2)= -sec(x) How do I verify this ?

 

[Ishuda]

csc(x+(3pi)/2)= -sec(x) How do I verify this ?

The easiest way I would suspect to be to write this as
$\displaystyle \frac{1}{sin(x + \frac{3 \pi}{2})}$ = ?
and use the sine of the sum of two angles formula.