tolongg pliss
poinnya lumayann
poinnya lumayann
Jawab:
Penjelasan dengan langkah-langkah:
1) Rumus : [tex]$1-2sin^2(x) = cos(2x)$[/tex], [tex]$cos^2(x)-sin^2(x) = cos(2x)$[/tex], [tex]tan(2x) = \frac{2tan(x)}{1-tan^2(x)}[/tex]
a) [tex]$cos(10A)$[/tex]
b) [tex]cos(6A)[/tex]
c) [tex]$tan(3A)$[/tex]
2) Jika [tex]sin(A) = 3/5[/tex] , maka [tex]cos(A) = 4/5[/tex] dan [tex]tan(A) = \frac{3}{4}[/tex].
[tex]\displaystyle sin(2A) = 2sin(A)cos(A)\\sin(2A) = 2 \times \frac{3}{5} \times \frac{4}{5} = \frac{24}{25}\\[/tex]
[tex]\displaystyle cos(2A) = cos^2(A) - sin^2(A)\\cos(2A) = \frac{16}{25} - \frac{9}{25} = \frac{7}{25}[/tex]
[tex]\displaystyle tan(2A) = \frac{2tan(A)}{1-tan(A)^2}\\tan(2A) = \frac{2 \times \frac{3}{4}}{1-\frac{3}{4}^2} = \frac{24}{7}[/tex]
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