Jika diketahui segitiga PQR siku-siku di Q dan sin P = 1/3 akar 5, maka cos P adalah...
Takamori37
Mengenal identitas:
![$\begin{align}\sin^2P+\cos^2P&=1 \\ \cos P&=\sqrt{1-\sin^2P} \\\cos P &=\sqrt{1-\left[\frac{1}{3}\sqrt{5}\right]^2} \\ \cos P&=\sqrt{1-\frac{5}{9}} \\ \cos P&=\sqrt{\frac{4}{9}} \\ \cos P&=\frac{2}{3} \end{align}](https://tex.z-dn.net/?f=%24%5Cbegin%7Balign%7D%5Csin%5E2P%2B%5Ccos%5E2P%26%3D1+%5C%5C+%5Ccos+P%26%3D%5Csqrt%7B1-%5Csin%5E2P%7D+%5C%5C%5Ccos+P+%26%3D%5Csqrt%7B1-%5Cleft%5B%5Cfrac%7B1%7D%7B3%7D%5Csqrt%7B5%7D%5Cright%5D%5E2%7D+%5C%5C+%5Ccos+P%26%3D%5Csqrt%7B1-%5Cfrac%7B5%7D%7B9%7D%7D+%5C%5C+%5Ccos+P%26%3D%5Csqrt%7B%5Cfrac%7B4%7D%7B9%7D%7D+%5C%5C+%5Ccos+P%26%3D%5Cfrac%7B2%7D%7B3%7D+%5Cend%7Balign%7D "$\begin{align}\sin^2P+\cos^2P&=1 \\ \cos P&=\sqrt{1-\sin^2P} \\\cos P &=\sqrt{1-\left[\frac{1}{3}\sqrt{5}\right]^2} \\ \cos P&=\sqrt{1-\frac{5}{9}} \\ \cos P&=\sqrt{\frac{4}{9}} \\ \cos P&=\frac{2}{3} \end{align}")
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Thanks 1
ZiendyLestuny
trima kasih...:D