Question

Sin(-45º)+cos 405º+tg(-945º)(вычеслить)
Упростить :(ctg a-cos a)*(si^2 a:cos a+tg a)

Answer 1

sin(-45°)+cos405°+tg(-945°)=-√2/2+cos(360°+45°)-tg(180°*5+45°)=-√2/2+√2/2-1=-1;
(ctgα-cosα)(sin²α÷cosα+tgα)=(ctgα-cosα)(tgαsinα+tgα)=(cosα(1-sinα)/sinα)*(sinα+1)*sinα/cosα=1-sin²α=cos²α