What is the value of 85cos(150) ?

The value of 85cos(150) is -(85sqrt(3))/2

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

85cos(150)

85 cos (15 0^{\circ})

- \frac{85 3}{2}

Decimal Notation

- 73.61215 \dots

Solution steps

85 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}

= 85 (- \frac{3}{2})

Simplify

85 (- \frac{3}{2}) : - \frac{85 3}{2}

85 (- \frac{3}{2})

Remove parentheses:

(- a) = - a

= - 85 \cdot \frac{3}{2}

Multiply fractions:

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

= - \frac{3 \cdot 85}{2}

= - \frac{85 3}{2}

2 sec^{2} (4 5^{\circ})

cos (\frac{3 π}{2} - π)

- π^{2} cos (π)

4 cos^{2} (6 0^{\circ}) + 4 sin^{2} (4 5^{\circ}) - sin^{2} (3 0^{\circ})

sin (\frac{3 π}{18})