Yang bisa mengerjakan tolong dibantu, tolong dibaca dan dijawab dengan benar, if u can’t, don’t give a stupid answer (I’m sorry cause some people doesn’t know what the answer and he gives a stupid answer like just saying “maaf kalo salah” padahal dia gk ngisi apa apa

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Soal tertera di gambar
saya kasih 80 point

Yang bisa mengerjakan tolong dibantu, tolong dibaca dan dijawab dengan benar, if u can’t, don’t give a stupid answer (I’m sorry cause some people doesn’t know what the answer and he gives a stupid answer like just saying “maaf kalo salah” padahal dia gk ngisi apa apa

Jawab:

Penjelasan dengan langkah-langkah:

soal 1

tan A = – 4/3

sin A =  4/5

cos A = – 3/5

tanB = 7/24

sin B = 7/25

cos B = 24/25

cos ( A – B) = cos A cos B + sin A sin B

= (-3/5).(24/25) + (  4/5)(7/25)

= -44/25

sin (A + B)  = sin A cos B + cos A sin B

= (4/5)(24/25) + (- 3/5)(7/25)

= 3/5

tan (A – B) = { tan A –  tan B) / ( 1 +  tanA . tan B)

= { – 4/3 – 7/24 } / ( 1  +(4/3)(7/24)

=  - 24/13

soal 2a

sf dfrac{cos75 - cos 15}{sin 75+ sin 15 }=\\\= dfrac{- 2 sin 45 sin 30}{2 sin 45 cos 30 }\\= - tan30= - dfrac{1}{sqrt3}

soal 2b

sf dfrac{sin 7A - sin 3A}{sin9a + sin 3A}=\\\= dfrac{2 cos 5A sin 2A}{2 sin 6A cos 3A}

soal3

sin A = 1/2 , A tumpul  –> A = 150

cos B = 1/2 √3, B lancip –> B =  30

cos (A – B)= cos (150-30)= cos 120 = – 1/2