en

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

-2cos(120)

Solution

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

Solution

1

Solution steps

- 2 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}

= - 2 (- \frac{1}{2})

Simplify

- 2 (- \frac{1}{2}) : 1

- 2 (- \frac{1}{2})

Apply rule

- (- a) = a

= 2 \cdot \frac{1}{2}

Multiply fractions:

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

= \frac{1 \cdot 2}{2}

Cancel the common factor:

2

= 1

= 1

Popular Examples

cos (0.76)

cos (0.72)

1+tan^2(60)-sec^2(60)

1 + tan^{2} (6 0^{\circ}) - sec^{2} (6 0^{\circ})

cos (\frac{π}{4}) - \frac{π}{4}

(3/2)((9.8)/(0.4))(1-sin(60)+cos(60))

(\frac{3}{2}) (\frac{9.8}{0.4}) (1 - sin (6 0^{\circ}) + cos (6 0^{\circ}))

Frequently Asked Questions (FAQ)

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