What is the value of 5*cos(60) ?

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5*cos(60)

5 \cdot cos (6 0^{\circ})

\frac{5}{2}

Decimal Notation

2.5

Solution steps

5 cos (6 0^{\circ})

Use the following trivial identity:

cos (6 0^{\circ}) = \frac{1}{2}

cos (6 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}

= 5 \cdot \frac{1}{2}

Simplify

5 \cdot \frac{1}{2} : \frac{5}{2}

5 \cdot \frac{1}{2}

Convert element to fraction:

5 = \frac{5}{1}

= \frac{5}{1} \cdot \frac{1}{2}

Multiply fractions:

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

= \frac{5 \cdot 1}{1 \cdot 2}

Cancel the common factor:

1

= \frac{5}{2}

= \frac{5}{2}

sin (arccos (\frac{- 3}{2}))

4 sin (\frac{π}{6}) cos (\frac{π}{6})

\frac{228}{tan ( 1 5 ^{\circ} )}

arcsin (\frac{51}{55})

sin (8 0^{\circ}) cos (5 0^{\circ}) - cos (8 0^{\circ}) sin (5 0^{\circ})