What is the value of cos(30)*15 ?

The value of cos(30)*15 is (15sqrt(3))/2

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

cos(30)*15

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

\frac{15 3}{2}

Decimal Notation

12.99038 \dots

Solution steps

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

Use the following trivial identity:

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

cos (3 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} \cdot 15

Simplify

\frac{3}{2} \cdot 15 : \frac{15 3}{2}

\frac{3}{2} \cdot 15

Multiply fractions:

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

= \frac{3 \cdot 15}{2}

= \frac{15 3}{2}

arcsin (- 0.8)

\frac{20}{tan ( 4 0 ^{\circ} )}

- 2 cos (\frac{7 π}{6})

cos (- 0.8)

cos (- 0.2)