Question

cos (180-45)
-tg (3п/2+п/4)
sin 150

Answer 1

$cos (180-45)=-cos45=- frac{ sqrt{2} }{2}$
$-tg ( frac{3 pi }{2} + frac{ pi }{4} )=-(-ctgfrac{ pi }{4} )=ctgfrac{ pi }{4}=1$
$sin 150=sin (180-30)=sin30= frac{1}{2}$