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Popular >

cos(2/3 pi)

Solution

cos (\frac{2}{3} π)

Solution

- \frac{1}{2}

+1

Decimal Notation

- 0.5

Solution steps

cos (\frac{2}{3} π)

Simplify:

\frac{2}{3} π = \frac{2 π}{3}

\frac{2}{3} π

Multiply fractions:

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

= \frac{2 π}{3}

= cos (\frac{2 π}{3})

Use the following trivial identity:

cos (\frac{2 π}{3}) = - \frac{1}{2}

cos (\frac{2 π}{3})

cos (x)

periodicity table with

2 πn

cycle:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= - \frac{1}{2}

= - \frac{1}{2}

Popular Examples

sin (\frac{4 π}{2})

arccos (\frac{12}{13})

4 sin (3 0^{\circ})

sin (\frac{1}{2} π)

- sin (2 π)

Frequently Asked Questions (FAQ)

What is the value of cos(2/3 pi) ?
The value of cos(2/3 pi) is -1/2