What is the value of cot((2pi)/3)-sin((3pi)/2) ?

The value of cot((2pi)/3)-sin((3pi)/2) is -(sqrt(3))/3+1

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cot((2pi)/3)-sin((3pi)/2)

cot (\frac{2 π}{3}) - sin (\frac{3 π}{2})

- \frac{3}{3} + 1

Decimal Notation

0.42264 \dots

Solution steps

cot (\frac{2 π}{3}) - sin (\frac{3 π}{2})

Rewrite using trig identities:

sin (\frac{3 π}{2}) = 2 sin (\frac{3 π}{4}) cos (\frac{3 π}{4})

sin (\frac{3 π}{2})

Write

sin (\frac{3 π}{2})

sin (2 \cdot \frac{3 π}{4})

= sin (2 \cdot \frac{3 π}{4})

Use the Double Angle identity:

sin (2 x) = 2 sin (x) cos (x)

= 2 sin (\frac{3 π}{4}) cos (\frac{3 π}{4})

= cot (\frac{2 π}{3}) - 2 sin (\frac{3 π}{4}) cos (\frac{3 π}{4})

Use the following trivial identity:

cot (\frac{2 π}{3}) = - \frac{3}{3}

cot (\frac{2 π}{3})

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

= - \frac{3}{3}

Use the following trivial identity:

sin (\frac{3 π}{4}) = \frac{2}{2}

sin (\frac{3 π}{4})

sin (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} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{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} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= \frac{2}{2}

Use the following trivial identity:

cos (\frac{3 π}{4}) = - \frac{2}{2}

cos (\frac{3 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}

= - \frac{3}{3} - 2 \cdot \frac{2}{2} (- \frac{2}{2})

Simplify

- \frac{3}{3} - 2 \cdot \frac{2}{2} (- \frac{2}{2}) : - \frac{3}{3} + 1

- \frac{3}{3} - 2 \cdot \frac{2}{2} (- \frac{2}{2})

Apply rule

- (- a) = a

= - \frac{3}{3} + 2 \cdot \frac{2}{2} \cdot \frac{2}{2}

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

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

Multiply fractions:

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

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

Cancel the common factor:

2

= \frac{2 2}{2}

22 = 2

22

Apply radical rule:

a a = a

22 = 2

= 2

= \frac{2}{2}

Apply rule

\frac{a}{a} = 1

= 1

= - \frac{3}{3} + 1

= - \frac{3}{3} + 1

sin (51.3 4^{\circ})

\frac{sin ( 5 ( - 0.1 ) )}{- 0.1}

sin^{2} (\frac{17 π}{2}) + cos^{2} (\frac{17 π}{2})

sin ((\frac{π}{2})^{2})

sin (\frac{19}{12} π)

What is the value of cot((2pi)/3)-sin((3pi)/2) ?
The value of cot((2pi)/3)-sin((3pi)/2) is -(sqrt(3))/3+1