सिद्ध कीजिए: ` cos510^(@) cos 330^(@) + sin 390^(@) cos 120^(@) =-`

cos510^(@)cos330^(@)+sin390^(@)cos120^(@)

Prove that, cos510^(@)cos330^(@)+sin390^(@)cos120^(@)=-1 .

Prove that: cos510^(0)cos330^(@)+s in390^(@)cos120^(@)=-1

cos 510^@cos330^@+sin 390^@cos120^@ =

sin 120^(@) cos 150^(@)- cos 240^(@) sin 330^(@) =

sin 120^(@) cos 150^(@)- cos 240^(@) sin 330^(@) =

Show that cos510^@cos330^@-sin390^@cos120^@=-1/2

Prove that cos510^@cos330^@+sin390^@cos120^@=-1

Prove that: cos510^0cos 330^0+sin 390^0cos 120^0=-1.

Prove that: (a) cos510^(@) sin510^(@) + sin(-330^(@)) cos(-390^(@))=0 b) tan(11pi)/(3) -2sin(9pi)/3-3/4"cosec"^(2)pi/4 + 4cos^(2)(17pi)/6=(3-2sqrt(3))/2