What is the value of cos(1230) ?

The value of cos(1230) is -(sqrt(3))/2

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

cos(1230)

cos (123 0^{\circ})

- \frac{3}{2}

Decimal Notation

- 0.86602 \dots

Solution steps

cos (123 0^{\circ})

cos (123 0^{\circ}) = cos (15 0^{\circ})

cos (123 0^{\circ})

Rewrite

123 0^{\circ}

36 0^{\circ} \cdot 3 + 15 0^{\circ}

= cos (36 0^{\circ} 3 + 15 0^{\circ})

Apply the periodicity of

cos

cos (x + 36 0^{\circ} \cdot k) = cos (x)

cos (36 0^{\circ} \cdot 3 + 15 0^{\circ}) = cos (15 0^{\circ})

= cos (15 0^{\circ})

= cos (15 0^{\circ})

Use the following trivial identity:

cos (15 0^{\circ}) = - \frac{3}{2}

cos (15 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{3}{2}

= - \frac{3}{2}

cos (36. 7^{\circ})

arccos (4.6)

cos (\frac{21 π}{2})

arccos (\frac{3}{12})

8 + 4 cos (\frac{π}{2})