Vì 75∘+15∘=90∘75∘+15∘=90∘ nên sin75∘=cos15∘sin⁡75∘=cos⁡15∘

Vì 53∘+37∘=90∘53∘+37∘=90∘ nên cos53∘=sin37∘cos⁡53∘=sin⁡37

Vì 47∘20'+42∘20'=90∘47∘20′+42∘20′=90∘ nên sin47∘20'=cos42∘40′sin⁡47∘20′=cos⁡42∘40′

Vì 62∘+28∘=90∘62∘+28∘=90∘ nên tg62∘=cotg28∘tg62∘=cot⁡g28∘

Vì 82∘45'+7∘15'=90∘82∘45′+7∘15′=90∘ nên cotg82∘45'=tg7∘15′cot⁡g82∘45′=tg7∘15′