Question

Answer this question.....​

Answer 1

$\frac{ sinx - sinz}{ \cos(z) - \cos(x) } \\ = \frac{2 \cos( \frac{x + z}{2}) \sin( \frac{x - z}{2} ) }{2 \sin( \frac{x + z}{2} ) \sin( \frac{x - z}{2} ) }$

$= \cot( \frac{x + z}{2} )$

$= cot(y)$