English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular Trigonometry >

(-1/5)*cos(2 pi/5 (x+1))+1>= 16/15

Solution

(- \frac{1}{5}) \cdot cos (2 \frac{π}{5} (x + 1)) + 1 \geq \frac{16}{15}

Solution

\frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n \leq x \leq \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Interval Notation

[\frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n, \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n]

Decimal

0.52043 \dots + 5 n \leq x \leq 2.47956 \dots + 5 n

Solution steps

(- \frac{1}{5}) cos (2 \cdot \frac{π}{5} (x + 1)) + 1 \geq \frac{16}{15}

Move

1

to the right side

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) + 1 \geq \frac{16}{15}

Subtract

1

from both sides

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) + 1 - 1 \geq \frac{16}{15} - 1

Simplify

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) + 1 - 1 \geq \frac{16}{15} - 1

Simplify

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) + 1 - 1 : (- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1))

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) + 1 - 1

Add similar elements:

1 - 1 \geq 0

= (- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1))

Simplify

\frac{16}{15} - 1 : \frac{1}{15}

\frac{16}{15} - 1

Convert element to fraction:

1 = \frac{1 \cdot 15}{15}

= - \frac{1 \cdot 15}{15} + \frac{16}{15}

Since the denominators are equal, combine the fractions:

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

= \frac{- 1 \cdot 15 + 16}{15}

- 1 \cdot 15 + 16 = 1

- 1 \cdot 15 + 16

Multiply the numbers:

1 \cdot 15 = 15

= - 15 + 16

Add/Subtract the numbers:

- 15 + 16 = 1

= 1

= \frac{1}{15}

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) \geq \frac{1}{15}

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) \geq \frac{1}{15}

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) \geq \frac{1}{15}

Multiply both sides by

- 1

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) \geq \frac{1}{15}

Multiply both sides by -1 (reverse the inequality)

(- \frac{1}{5}) cos (2 \frac{π}{5} (x + 1)) (- 1) \leq \frac{1 \cdot ( - 1 )}{15}

Simplify

\frac{1}{5} cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{15}

\frac{1}{5} cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{15}

Multiply both sides by

5

\frac{1}{5} cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{15}

Multiply both sides by

5

5 \cdot \frac{1}{5} cos (2 \frac{π}{5} (x + 1)) \leq 5 (- \frac{1}{15})

Simplify

5 \cdot \frac{1}{5} cos (2 \frac{π}{5} (x + 1)) \leq 5 (- \frac{1}{15})

Simplify

5 \cdot \frac{1}{5} cos (2 \frac{π}{5} (x + 1)) : cos (2 \frac{π}{5} (x + 1))

5 \cdot \frac{1}{5} cos (2 \frac{π}{5} (x + 1))

Multiply fractions:

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

= \frac{1 \cdot 5}{5} cos (2 \frac{π}{5} (x + 1))

Cancel the common factor:

5

= cos (2 \frac{π}{5} (x + 1)) \cdot 1

Multiply:

cos (2 \frac{π}{5} (x + 1)) \cdot 1 = cos (2 \frac{π}{5} (x + 1))

= cos (2 \frac{π}{5} (x + 1))

Simplify

5 (- \frac{1}{15}) : - \frac{1}{3}

5 (- \frac{1}{15})

Remove parentheses:

(- a) = - a

= - 5 \cdot \frac{1}{15}

Multiply fractions:

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

= - \frac{1 \cdot 5}{15}

Multiply the numbers:

1 \cdot 5 = 5

= - \frac{5}{15}

Cancel the common factor:

5

= - \frac{1}{3}

cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{3}

cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{3}

cos (2 \frac{π}{5} (x + 1)) \leq - \frac{1}{3}

For

cos (x) \leq a

, if

- 1 < a < 1

then

arccos (a) + 2 πn \leq x \leq 2 π - arccos (a) + 2 πn

arccos (- \frac{1}{3}) + 2 πn \leq 2 \cdot \frac{π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn

a \leq u \leq b

then

a \leq u and u \leq b

arccos (- \frac{1}{3}) + 2 πn \leq 2 \cdot \frac{π}{5} (x + 1) and 2 \cdot \frac{π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn

arccos (- \frac{1}{3}) + 2 πn \leq 2 \cdot \frac{π}{5} (x + 1) : x \geq \frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n

arccos (- \frac{1}{3}) + 2 πn \leq 2 \cdot \frac{π}{5} (x + 1)

Switch sides

2 \cdot \frac{π}{5} (x + 1) \geq arccos (- \frac{1}{3}) + 2 πn

Simplify

2 \cdot \frac{π}{5} : \frac{2 π}{5}

2 \cdot \frac{π}{5}

Multiply fractions:

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

= \frac{π 2}{5}

\frac{2 π}{5} (x + 1) \geq arccos (- \frac{1}{3}) + 2 πn

Multiply both sides by

5

\frac{2 π}{5} (x + 1) \geq arccos (- \frac{1}{3}) + 2 πn

Multiply both sides by

5

5 \cdot \frac{2 π}{5} (x + 1) \geq 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Simplify

5 \cdot \frac{2 π}{5} (x + 1) \geq 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Simplify

5 \cdot \frac{2 π}{5} (x + 1) : 2 π (x + 1)

5 \cdot \frac{2 π}{5} (x + 1)

Multiply fractions:

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

= \frac{2 \cdot 5 π}{5} (x + 1)

Cancel the common factor:

5

= (x + 1) \cdot 2 π

Simplify

5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn : 5 arccos (- \frac{1}{3}) + 10 πn

5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Multiply the numbers:

5 \cdot 2 = 10

= 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \geq 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \geq 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \geq 5 arccos (- \frac{1}{3}) + 10 πn

Divide both sides by

2 π

2 π (x + 1) \geq 5 arccos (- \frac{1}{3}) + 10 πn

Divide both sides by

2 π

\frac{2 π ( x + 1 )}{2 π} \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Simplify

\frac{2 π ( x + 1 )}{2 π} \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Simplify

\frac{2 π ( x + 1 )}{2 π} : x + 1

\frac{2 π ( x + 1 )}{2 π}

Divide the numbers:

\frac{2}{2} = 1

= \frac{π ( x + 1 )}{π}

Cancel the common factor:

π

= x + 1

Simplify

\frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π} : \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

\frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Cancel

\frac{10 πn}{2 π} : 5 n

\frac{10 πn}{2 π}

Cancel

\frac{10 πn}{2 π} : 5 n

\frac{10 πn}{2 π}

Divide the numbers:

\frac{10}{2} = 5

= \frac{5 πn}{π}

Cancel the common factor:

π

= 5 n

= 5 n

= \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Move

1

to the right side

x + 1 \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Subtract

1

from both sides

x + 1 - 1 \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

Simplify

x \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

x \geq \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

Simplify

\frac{5 arccos ( - \frac{1}{3} )}{2 π} - 1 : \frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π}

\frac{5 arccos ( - \frac{1}{3} )}{2 π} - 1

Convert element to fraction:

1 = \frac{1 \cdot 2 π}{2 π}

= \frac{5 arccos ( - \frac{1}{3} )}{2 π} - \frac{1 \cdot 2 π}{2 π}

Since the denominators are equal, combine the fractions:

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

= \frac{5 arccos ( - \frac{1}{3} ) - 1 \cdot 2 π}{2 π}

Multiply the numbers:

1 \cdot 2 = 2

= \frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π}

x \geq \frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n

2 \cdot \frac{π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn : x \leq \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

2 \cdot \frac{π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn

Simplify

2 \cdot \frac{π}{5} : \frac{2 π}{5}

2 \cdot \frac{π}{5}

Multiply fractions:

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

= \frac{π 2}{5}

\frac{2 π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn

Multiply both sides by

5

\frac{2 π}{5} (x + 1) \leq 2 π - arccos (- \frac{1}{3}) + 2 πn

Multiply both sides by

5

5 \cdot \frac{2 π}{5} (x + 1) \leq 5 \cdot 2 π - 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Simplify

5 \cdot \frac{2 π}{5} (x + 1) \leq 5 \cdot 2 π - 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Simplify

5 \cdot \frac{2 π}{5} (x + 1) : 2 π (x + 1)

5 \cdot \frac{2 π}{5} (x + 1)

Multiply fractions:

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

= \frac{2 \cdot 5 π}{5} (x + 1)

Cancel the common factor:

5

= (x + 1) \cdot 2 π

Simplify

5 \cdot 2 π - 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn : 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

5 \cdot 2 π - 5 arccos (- \frac{1}{3}) + 5 \cdot 2 πn

Multiply the numbers:

5 \cdot 2 = 10

= 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \leq 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \leq 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

2 π (x + 1) \leq 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

Divide both sides by

2 π

2 π (x + 1) \leq 10 π - 5 arccos (- \frac{1}{3}) + 10 πn

Divide both sides by

2 π

\frac{2 π ( x + 1 )}{2 π} \leq \frac{10 π}{2 π} - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Simplify

\frac{2 π ( x + 1 )}{2 π} \leq \frac{10 π}{2 π} - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Simplify

\frac{2 π ( x + 1 )}{2 π} : x + 1

\frac{2 π ( x + 1 )}{2 π}

Divide the numbers:

\frac{2}{2} = 1

= \frac{π ( x + 1 )}{π}

Cancel the common factor:

π

= x + 1

Simplify

\frac{10 π}{2 π} - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π} : 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

\frac{10 π}{2 π} - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Cancel

\frac{10 π}{2 π} : 5

\frac{10 π}{2 π}

Cancel

\frac{10 π}{2 π} : 5

\frac{10 π}{2 π}

Divide the numbers:

\frac{10}{2} = 5

= \frac{5 π}{π}

Cancel the common factor:

π

= 5

= 5

= 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + \frac{10 πn}{2 π}

Cancel

\frac{10 πn}{2 π} : 5 n

\frac{10 πn}{2 π}

Cancel

\frac{10 πn}{2 π} : 5 n

\frac{10 πn}{2 π}

Divide the numbers:

\frac{10}{2} = 5

= \frac{5 πn}{π}

Cancel the common factor:

π

= 5 n

= 5 n

= 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

x + 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Move

1

to the right side

x + 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Subtract

1

from both sides

x + 1 - 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

Simplify

x + 1 - 1 \leq 5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

Simplify

x + 1 - 1 : x

x + 1 - 1

Add similar elements:

1 - 1 \leq 0

= x

Simplify

5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1 : 5 n + 4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

5 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} + 5 n - 1

Subtract the numbers:

5 - 1 = 4

= 5 n + 4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

x \leq 5 n + 4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

x \leq 5 n + 4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

x \leq 5 n + 4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

Simplify

4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π} : \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π}

4 - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

Convert element to fraction:

4 = \frac{4 \cdot 2 π}{2 π}

= \frac{4 \cdot 2 π}{2 π} - \frac{5 arccos ( - \frac{1}{3} )}{2 π}

Since the denominators are equal, combine the fractions:

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

= \frac{4 \cdot 2 π - 5 arccos ( - \frac{1}{3} )}{2 π}

Multiply the numbers:

4 \cdot 2 = 8

= \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π}

x \leq \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Combine the intervals

x \geq \frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n and x \leq \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Merge Overlapping Intervals

\frac{5 arccos ( - \frac{1}{3} ) - 2 π}{2 π} + 5 n \leq x \leq \frac{8 π - 5 arccos ( - \frac{1}{3} )}{2 π} + 5 n

Popular Examples

cos^2(x)>= sin^2(x)

cos(x)>2

sqrt(3)cos(x)+sin(x)<0

3sqrt(3)cos(x)-13/2 <-2

sin(a)-cos(a)>0