Question

can somebody please explain how to do this:)​

Answer 1

$\\ \sf\longmapsto \dfrac{sin40.sin120}{sin110-sin340}$

$\\ \sf\longmapsto \dfrac{sin(90-50).sin(90+30)}{sin(90+20).sin(360-20)}$

$\\ \sf\longmapsto \dfrac{cos50.cos30}{cos20.(-sin20}$

$\\ \sf\longmapsto \dfrac{cos50cos30}{-sin20cos20}$

$\\ \sf\longmapsto -\dfrac{cos30cos50}{sin20cos20}$