matematika trigonometri

Sin A = 3 / 5
Cos A = 4 / 5
Sin B = 7/25
Cos B = 24/25


Cos ( A+B )
= Cos A.Cos B - Sin A.Sin B
= 4/5. 24/25 - 3/5. 7/25
= 96/125 - 21/125
= 75/ 125
= 3/5

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