Question

sin patrat de 100 de grade + cosinus patrat de 80 de grade = ?

Answer 1

sin² 100° = sin²(180° -1 00°) = sin² 80°

Acum, avem :

sin²80° + cos²80° = 1

Answer 2

sin^2 100+cos^2 80=[sin(180-80)]2+cos^2 80=sin^2 80+cos^2 80=1
am folosit formula de reducere sin(π+α)=sinα