Question

sin(-810)+cos(-900)+tg(-395)*ctg575
sin(-2383)-sin(-2023)+cos(-485)-cos(-125)
3tg930+sin1200-cos1410

Answer 1

$sin(-810)+cos(-900)+tg(-395)*ctg575=$
$=-sin(360*2+90)+cos(360*2+180)-tg(180*2+35)*ctg(180*3+35)=$
$=-sin90+cos180-tg35*ctg35=-1-1-1=-3$
$sin(-2383)-sin(-2023)+cos(-485)-cos(-125)=$
$=-sin(360*6+223)+sin(360*5+223)+cos(360+125)-cos125=$
$=-sin223+sin223+cos125-cos125=0$
$3tg930+sin1200-cos1410=$ 
$=3tg(180*5+30)+sin(360*3+120)-cos(360*4-30)=$
$=3tg30+sin120-cos(-30)=3* frac{ sqrt{3} }{3} +sin(90+30)-cos30=$
$sqrt{3}+cos30-cos30=sqrt{3}.$ -