What is the value of cos(pi/4)+cos(pi/6) ?

The value of cos(pi/4)+cos(pi/6) is (sqrt(2)+sqrt(3))/2

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cos(pi/4)+cos(pi/6)

cos (\frac{π}{4}) + cos (\frac{π}{6})

\frac{2 + 3}{2}

Decimal Notation

1.57313 \dots

Solution steps

cos (\frac{π}{4}) + cos (\frac{π}{6})

Use the following trivial identity:

cos (\frac{π}{4}) = \frac{2}{2}

cos (\frac{π}{4})

cos (x)

periodicity table with

2 πn

cycle:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} 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}

Use the following trivial identity:

cos (\frac{π}{6}) = \frac{3}{2}

cos (\frac{π}{6})

cos (x)

periodicity table with

2 πn

cycle:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} 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{2}{2} + \frac{3}{2}

Simplify

\frac{2}{2} + \frac{3}{2} : \frac{2 + 3}{2}

\frac{2}{2} + \frac{3}{2}

Apply rule

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

= \frac{2 + 3}{2}

= \frac{2 + 3}{2}

20 sin (3 0^{\circ})

tan (- 48 0^{\circ})

arctan (0.3)

cos (arcsin (- \frac{1}{3}))

tan (arccos (\frac{3}{4}))

What is the value of cos(pi/4)+cos(pi/6) ?
The value of cos(pi/4)+cos(pi/6) is (sqrt(2)+sqrt(3))/2