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sin^2(40grade)+cos^2(140 grade)

Răspuns :

O formula: sin(x grade)=sin(180 grade - x grade)
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Din formula => sin(40 grade)=sin(180 grade - 40 grade)=sin(140 grade).

Deci sin^2(40 grade)+cos^2(140 grade)=sin^2(140 grade)+cos^2(140 grade)=1.