jika
Matematika
jabar16
Pertanyaan
jika<A=60° dan sudut ,B=30°.buktikan : cos(A+B)=cos A cos B-sin A sin B
1 Jawaban
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1. Jawaban Bayu5
A = 60
B = 30
Cos(A+B) = cos(60+30) = cos90 = 0
Cos(A+B) = cosA.cosB - sinA.sinB
Cos(60+30) = cos60.cos30 - sin 60sin 30
Cos(90) = 1/2.√3/2 - √3/2.1/2
0 = √3/4 - √3/4
0 = 0 (Terbukti)