Question

cos (180-45)
-tg (3п/2+п/4)
sin 150

Answer 1

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