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Popular >

4cos(135)

Solution

4 cos (13 5^{\circ})

Solution

- 22

+1

Decimal Notation

- 2.82842 \dots

Solution steps

4 cos (13 5^{\circ})

Use the following trivial identity:

cos (13 5^{\circ}) = - \frac{2}{2}

cos (13 5^{\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{2}{2}

= 4 (- \frac{2}{2})

Simplify

4 (- \frac{2}{2}) : - 22

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

Remove parentheses:

(- a) = - a

= - 4 \cdot \frac{2}{2}

Multiply fractions:

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

= - \frac{2 \cdot 4}{2}

Divide the numbers:

\frac{4}{2} = 2

= - 22

= - 22

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Frequently Asked Questions (FAQ)

What is the value of 4cos(135) ?
The value of 4cos(135) is -2sqrt(2)