Question

Jika tan 20° = p maka nilai
sin 70° + sin 10°
-------------------------
cos 70° + cos 10°

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Answer 1

Verified answer

Jika tan 20° = p maka nilai
sin 70° + sin 10°
-------------------------
cos 70° + cos 10°

= (2 sin ½(70 + 10) . Cos ½(70 - 10)) / (2 cos ½(70 + 10). cos ½(70 - 10))
= (2 sin (40) cos (30)) / (2 cos (40) . cos (30)

* 2 dan cos 30 dicoret karna sama sehingga

= sin 40/ cos 40
= tan 40
= tan (20 + 20)
= (tan 20 + tan 20) / (1 - tan 20 . Tan 20)
= (p + p) / (1 - p . P)
= (2p) / 1 - p²