Pertanyaan

Jika tan θ = a untuk θ sudut lancip, nilai cos 3 θ sama dengan...

Jika $tan θ = a$ untuk $θ$ sudut lancip, nilai $cos 3 θ$ sama dengan...

$open parentheses fraction numerator 1 minus 3 a squared over denominator 1 plus a squared end fraction close parentheses square root of 1 plus a squared end root$
$open parentheses fraction numerator 1 minus 3 a squared over denominator open parentheses 1 plus a close parentheses squared end fraction close parentheses square root of 1 plus a squared end root$
$open parentheses fraction numerator 1 plus 3 a squared over denominator 1 plus a squared end fraction close parentheses square root of 1 plus a squared end root$
$open parentheses fraction numerator 1 minus 3 a squared over denominator open parentheses 1 plus a squared close parentheses squared end fraction close parentheses square root of 1 plus a squared end root$
$open parentheses fraction numerator 1 plus 3 a squared over denominator open parentheses 1 plus a squared close parentheses squared end fraction close parentheses square root of 1 plus a squared end root$

H. Janatu

Master Teacher

Mahasiswa/Alumni Universitas Riau

Jawaban terverifikasi

Jawaban

jawaban yang tepat adalah D.

Pembahasan

Ingat rumus-rumus trigonometri berikut : Berdasarkan rumus di atas, maka Selanjutnya diketahui bahwa dan sudut lancip, dengan segitiga siku-siku bantu, Sehingga, Jadi, jawaban yang tepat adalah D.

Ingat rumus-rumus trigonometri berikut :

Berdasarkan rumus di atas, maka

Selanjutnya diketahui bahwa tan space theta equals a dan theta sudut lancip, dengan segitiga siku-siku bantu,

Sehingga,

$begin mathsize 12px style table attributes columnalign right center left columnspacing 0px end attributes row cell cos space 3 theta end cell equals cell 2 cos cubed space theta minus cos space theta minus 2 sin squared space theta space cos space theta end cell row blank equals cell 2 open parentheses fraction numerator 1 over denominator square root of 1 plus a squared end root end fraction close parentheses cubed minus fraction numerator 1 over denominator square root of 1 plus a squared end root end fraction minus 2 open parentheses fraction numerator a over denominator square root of 1 plus a squared end root end fraction close parentheses squared open parentheses fraction numerator 1 over denominator square root of 1 plus a squared end root end fraction close parentheses end cell row blank equals cell fraction numerator 2 minus open parentheses 1 plus a squared close parentheses minus 2 a squared over denominator open parentheses 1 plus a squared close parentheses square root of 1 plus a squared end root end fraction end cell row blank equals cell fraction numerator 1 minus 3 a squared over denominator open parentheses 1 plus a squared close parentheses square root of 1 plus a squared end root end fraction cross times fraction numerator square root of 1 plus a squared end root over denominator square root of 1 plus a squared end root end fraction end cell row blank equals cell open parentheses fraction numerator 1 minus 3 a squared over denominator open parentheses 1 plus a squared close parentheses squared end fraction close parentheses square root of 1 plus a squared end root end cell end table end style$

Jadi, jawaban yang tepat adalah D.

Latihan Bab

Konsep Kilat

Jumlah dan Selisih Dua Sudut

Sudut Rangkap dan Sudut Paruh

Perkalian Trigonometri