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受欢迎的三角函数 >

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

解答

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

解答

\frac{1 - cos ( \frac{4 π}{3} )}{2}

+1

十进制

0.75

求解步骤

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

改写为

= cos (2 \cdot \frac{2 π}{3})

使用三角恒等式改写:

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

cos (2 \cdot \frac{2 π}{3})

使用倍角公式:

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}))

化简:

\frac{2 π 2}{3} = \frac{4 π}{3}

\frac{2 π 2}{3}

数字相乘:

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}))

分式相乘:

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}))

乘以:

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

= (1 - cos (\frac{4 π}{3}))

去除括号:

(a) = a

= 1 - cos (\frac{4 π}{3})

= \frac{1 - cos ( \frac{4 π}{3} )}{2}

= \frac{1 - cos ( \frac{4 π}{3} )}{2}

流行的例子

sin (30. 1^{\circ})

(21.3sin(36.7))/(5cos(30))

\frac{21.3 sin ( 36. 7 ^{\circ} )}{5 cos ( 3 0 ^{\circ} )}

cos (0.86)

cos (0.83)

cos (\frac{39 π}{6})