1/2 (1-cos((2pi2)/3))

解

\frac{1}{2} (1 - cos (\frac{2 \cdot π \cdot 2}{3}))

\frac{1 - cos ( \frac{4 π}{3} )}{2}

十進法表記

0.75

解答ステップ

\frac{1}{2} (1 - cos (\frac{2 π 2}{3}))

書き換え

= cos (2 \cdot \frac{2 π}{3})

三角関数の公式を使用して書き換える:

cos (2 \cdot \frac{2 π}{3}) = 1 - 2 sin^{2} (\frac{2 π}{3})

cos (2 \cdot \frac{2 π}{3})

2倍角の公式を使用:

cos (2 x) = 1 - 2 sin^{2} (x)

= 1 - 2 sin^{2} (\frac{2 π}{3})

= \frac{1}{2} (1 - cos (\frac{2 π 2}{3}))

簡素化:

\frac{2 π 2}{3} = \frac{4 π}{3}

\frac{2 π 2}{3}

数を乗じる:

2 \cdot 2 = 4

= \frac{4 π}{3}

\frac{1}{2} (1 - cos (\frac{4 π}{3})) = \frac{1 - cos ( \frac{4 π}{3} )}{2}

\frac{1}{2} (1 - cos (\frac{4 π}{3}))

分数を乗じる:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{1 \cdot ( 1 - cos ( \frac{4 π}{3} ) )}{2}

1 \cdot (1 - cos (\frac{4 π}{3})) = 1 - cos (\frac{4 π}{3})

1 \cdot (1 - cos (\frac{4 π}{3}))

乗算:

1 \cdot (1 - cos (\frac{4 π}{3})) = (1 - cos (\frac{4 π}{3}))

= (1 - cos (\frac{4 π}{3}))

括弧を削除する:

(a) = a

= 1 - cos (\frac{4 π}{3})

= \frac{1 - cos ( \frac{4 π}{3} )}{2}

= \frac{1 - cos ( \frac{4 π}{3} )}{2}