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Popular >

cos(-120)

Solution

cos (- 12 0^{\circ})

Solution

- \frac{1}{2}

+1

Decimal Notation

- 0.5

Solution steps

cos (- 12 0^{\circ})

Use the following property:

cos (- x) = cos (x)

cos (- 12 0^{\circ}) = cos (12 0^{\circ})

= cos (12 0^{\circ})

Use the following trivial identity:

cos (12 0^{\circ}) = - \frac{1}{2}

cos (12 0^{\circ})

cos (x)

periodicity table with

36 0^{\circ} n

cycle:

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} 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

2 cos (\frac{π}{6})

arctan((-1)/(sqrt(3)))

arctan (\frac{- 1}{3})

sin (3 3^{\circ})

- sin (1)

cos(arcsin((sqrt(2))/2))

cos (arcsin (\frac{2}{2}))

Frequently Asked Questions (FAQ)

What is the value of cos(-120) ?
The value of cos(-120) is -1/2