What is the value of cos(pi/3)+cot((9pi)/4) ?

The value of cos(pi/3)+cot((9pi)/4) is 3/2

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cos(pi/3)+cot((9pi)/4)

cos (\frac{π}{3}) + cot (\frac{9 π}{4})

\frac{3}{2}

Decimal

1.5

Solution steps

cos (\frac{π}{3}) + cot (\frac{9 π}{4})

Use the following trivial identity:

cos (\frac{π}{3}) = \frac{1}{2}

cos (\frac{π}{3})

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{1}{2}

Rewrite using trig identities:

cot (\frac{9 π}{4}) = 1

cot (\frac{9 π}{4})

cot (\frac{9 π}{4}) = cot (\frac{π}{4})

cot (\frac{9 π}{4})

Rewrite

\frac{9 π}{4}

π \cdot 2 + \frac{π}{4}

= cot (π 2 + \frac{π}{4})

Apply the periodicity of

cot

cot (x + π \cdot k) = cot (x)

cot (π \cdot 2 + \frac{π}{4}) = cot (\frac{π}{4})

= cot (\frac{π}{4})

= cot (\frac{π}{4})

Use the following trivial identity:

cot (\frac{π}{4}) = 1

cot (\frac{π}{4})

cot (x)

periodicity table with

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} cot (x) \mp \infty 31 \frac{3}{3} 0 - \frac{3}{3} - 1 - 3

= 1

= 1

= \frac{1}{2} + 1

Simplify

\frac{1}{2} + 1 : \frac{3}{2}

\frac{1}{2} + 1

Convert element to fraction:

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

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

Since the denominators are equal, combine the fractions:

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

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

1 \cdot 2 + 1 = 3

1 \cdot 2 + 1

Multiply the numbers:

1 \cdot 2 = 2

= 2 + 1

Add the numbers:

2 + 1 = 3

= 3

= \frac{3}{2}

= \frac{3}{2}

What is the value of cos(pi/3)+cot((9pi)/4) ?
The value of cos(pi/3)+cot((9pi)/4) is 3/2