What is the value of 6.5cos(45) ?

The value of 6.5cos(45) is (13sqrt(2))/4

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

6.5cos(45)

6.5 cos (4 5^{\circ})

\frac{13 2}{4}

Decimal Notation

4.59619 \dots

Solution steps

6.5 cos (4 5^{\circ})

= \frac{13}{2} cos (4 5^{\circ})

Use the following trivial identity:

cos (4 5^{\circ}) = \frac{2}{2}

cos (4 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}

= \frac{13}{2} \cdot \frac{2}{2}

Simplify

\frac{13}{2} \cdot \frac{2}{2} : \frac{13 2}{4}

\frac{13}{2} \cdot \frac{2}{2}

Multiply fractions:

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

= \frac{13 2}{2 \cdot 2}

Multiply the numbers:

2 \cdot 2 = 4

= \frac{13 2}{4}

= \frac{13 2}{4}

cos^{2} (3 1^{\circ})

sin (29 0^{\circ})

arccos (\frac{1}{8})

\frac{sin ( 10 5 ^{\circ} ) - sin ( 1 5 ^{\circ} )}{sin ( 10 5 ^{\circ} ) + sin ( 1 5 ^{\circ} )}

- 5.2 sin (3.71797) - 8 cos (3.71797)