What is the general solution for sin(x)-cos(x)= 7/5 ?

The general solution for sin(x)-cos(x)= 7/5 is x=1.42889…+2pin+pi/4 ,x=pi-1.42889…+2pin+pi/4

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sin(x)-cos(x)= 7/5

Solution

sin (x) - cos (x) = \frac{7}{5}

Solution

x = 1.42889 \dots + 2 πn + \frac{π}{4}, x = π - 1.42889 \dots + 2 πn + \frac{π}{4}

Degrees

x = 126.86989 \dots^{\circ} + 36 0^{\circ} n, x = 143.13010 \dots^{\circ} + 36 0^{\circ} n

Solution steps

sin (x) - cos (x) = \frac{7}{5}

Rewrite using trig identities

sin (x) - cos (x)

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

sin (x) - cos (x)

Rewrite as

= 2 (\frac{1}{2} sin (x) - \frac{1}{2} cos (x))

Use the following trivial identity:

cos (\frac{π}{4}) = \frac{1}{2}

Use the following trivial identity:

sin (\frac{π}{4}) = \frac{1}{2}

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

Use the Angle Sum identity:

sin (s - t) = sin (s) cos (t) - cos (s) sin (t)

= 2 sin (x - \frac{π}{4})

= 2 sin (x - \frac{π}{4})

2 sin (x - \frac{π}{4}) = \frac{7}{5}

Divide both sides by

2

2 sin (x - \frac{π}{4}) = \frac{7}{5}

Divide both sides by

2

\frac{2 sin ( x - \frac{π}{4} )}{2} = \frac{\frac{7}{5}}{2}

Simplify

\frac{2 sin ( x - \frac{π}{4} )}{2} = \frac{\frac{7}{5}}{2}

Simplify

\frac{2 sin ( x - \frac{π}{4} )}{2} : sin (x - \frac{π}{4})

\frac{2 sin ( x - \frac{π}{4} )}{2}

Cancel the common factor:

2

= sin (x - \frac{π}{4})

Simplify

\frac{\frac{7}{5}}{2} : \frac{7 2}{10}

\frac{\frac{7}{5}}{2}

Apply the fraction rule:

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

= \frac{7}{5 2}

Rationalize

\frac{7}{5 2} : \frac{7 2}{10}

\frac{7}{5 2}

Multiply by the conjugate

\frac{2}{2}

= \frac{7 2}{5 2 2}

522 = 10

522

Apply radical rule:

a a = a

22 = 2

= 5 \cdot 2

Multiply the numbers:

5 \cdot 2 = 10

= 10

= \frac{7 2}{10}

= \frac{7 2}{10}

sin (x - \frac{π}{4}) = \frac{7 2}{10}

sin (x - \frac{π}{4}) = \frac{7 2}{10}

sin (x - \frac{π}{4}) = \frac{7 2}{10}

Apply trig inverse properties

sin (x - \frac{π}{4}) = \frac{7 2}{10}

General solutions for

sin (x - \frac{π}{4}) = \frac{7 2}{10}

sin (x) = a \Rightarrow x = arcsin (a) + 2 πn, x = π - arcsin (a) + 2 πn

x - \frac{π}{4} = arcsin (\frac{7 2}{10}) + 2 πn, x - \frac{π}{4} = π - arcsin (\frac{7 2}{10}) + 2 πn

x - \frac{π}{4} = arcsin (\frac{7 2}{10}) + 2 πn, x - \frac{π}{4} = π - arcsin (\frac{7 2}{10}) + 2 πn

Solve

x - \frac{π}{4} = arcsin (\frac{7 2}{10}) + 2 πn : x = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x - \frac{π}{4} = arcsin (\frac{7 2}{10}) + 2 πn

Simplify

arcsin (\frac{7 2}{10}) + 2 πn : arcsin (\frac{7}{5 2}) + 2 πn

arcsin (\frac{7 2}{10}) + 2 πn

\frac{7 2}{10} = \frac{7}{5 2}

\frac{7 2}{10}

Factor

10 : 2 \cdot 5

Factor

10 = 2 \cdot 5

= \frac{7 2}{2 \cdot 5}

Cancel

\frac{7 2}{2 \cdot 5} : \frac{7}{2 \cdot 5}

\frac{7 2}{2 \cdot 5}

Apply radical rule:

2 = 2^{\frac{1}{2}}

= \frac{7 \cdot 2 ^{\frac{1}{2}}}{2 \cdot 5}

Apply exponent rule:

\frac{x ^{a}}{x ^{b}} = \frac{1}{x ^{b - a}}

\frac{2 ^{\frac{1}{2}}}{2 ^{1}} = \frac{1}{2 ^{1 - \frac{1}{2}}}

= \frac{7}{5 \cdot 2 ^{- \frac{1}{2} + 1}}

Subtract the numbers:

1 - \frac{1}{2} = \frac{1}{2}

= \frac{7}{5 \cdot 2 ^{\frac{1}{2}}}

Apply radical rule:

2^{\frac{1}{2}} = 2

= \frac{7}{5 2}

= \frac{7}{2 \cdot 5}

= arcsin (\frac{7}{5 2}) + 2 πn

x - \frac{π}{4} = arcsin (\frac{7}{5 2}) + 2 πn

Move

\frac{π}{4}

to the right side

x - \frac{π}{4} = arcsin (\frac{7}{5 2}) + 2 πn

Add

\frac{π}{4}

to both sides

x - \frac{π}{4} + \frac{π}{4} = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Simplify

x - \frac{π}{4} + \frac{π}{4} = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Simplify

x - \frac{π}{4} + \frac{π}{4} : x

x - \frac{π}{4} + \frac{π}{4}

Add similar elements:

- \frac{π}{4} + \frac{π}{4} = 0

= x

Simplify

arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4} : arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

= arcsin (\frac{7 2}{10}) + 2 πn + \frac{π}{4}

\frac{7 2}{10} = \frac{7}{5 2}

\frac{7 2}{10}

Factor

10 : 2 \cdot 5

Factor

10 = 2 \cdot 5

= \frac{7 2}{2 \cdot 5}

Cancel

\frac{7 2}{2 \cdot 5} : \frac{7}{2 \cdot 5}

\frac{7 2}{2 \cdot 5}

Apply radical rule:

2 = 2^{\frac{1}{2}}

= \frac{7 \cdot 2 ^{\frac{1}{2}}}{2 \cdot 5}

Apply exponent rule:

\frac{x ^{a}}{x ^{b}} = \frac{1}{x ^{b - a}}

\frac{2 ^{\frac{1}{2}}}{2 ^{1}} = \frac{1}{2 ^{1 - \frac{1}{2}}}

= \frac{7}{5 \cdot 2 ^{- \frac{1}{2} + 1}}

Subtract the numbers:

1 - \frac{1}{2} = \frac{1}{2}

= \frac{7}{5 \cdot 2 ^{\frac{1}{2}}}

Apply radical rule:

2^{\frac{1}{2}} = 2

= \frac{7}{5 2}

= \frac{7}{2 \cdot 5}

= arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Could not simplify further

= arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Solve

x - \frac{π}{4} = π - arcsin (\frac{7 2}{10}) + 2 πn : x = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x - \frac{π}{4} = π - arcsin (\frac{7 2}{10}) + 2 πn

Simplify

π - arcsin (\frac{7 2}{10}) + 2 πn : π - arcsin (\frac{7}{5 2}) + 2 πn

π - arcsin (\frac{7 2}{10}) + 2 πn

\frac{7 2}{10} = \frac{7}{5 2}

\frac{7 2}{10}

Factor

10 : 2 \cdot 5

Factor

10 = 2 \cdot 5

= \frac{7 2}{2 \cdot 5}

Cancel

\frac{7 2}{2 \cdot 5} : \frac{7}{2 \cdot 5}

\frac{7 2}{2 \cdot 5}

Apply radical rule:

2 = 2^{\frac{1}{2}}

= \frac{7 \cdot 2 ^{\frac{1}{2}}}{2 \cdot 5}

Apply exponent rule:

\frac{x ^{a}}{x ^{b}} = \frac{1}{x ^{b - a}}

\frac{2 ^{\frac{1}{2}}}{2 ^{1}} = \frac{1}{2 ^{1 - \frac{1}{2}}}

= \frac{7}{5 \cdot 2 ^{- \frac{1}{2} + 1}}

Subtract the numbers:

1 - \frac{1}{2} = \frac{1}{2}

= \frac{7}{5 \cdot 2 ^{\frac{1}{2}}}

Apply radical rule:

2^{\frac{1}{2}} = 2

= \frac{7}{5 2}

= \frac{7}{2 \cdot 5}

= π - arcsin (\frac{7}{5 2}) + 2 πn

x - \frac{π}{4} = π - arcsin (\frac{7}{5 2}) + 2 πn

Move

\frac{π}{4}

to the right side

x - \frac{π}{4} = π - arcsin (\frac{7}{5 2}) + 2 πn

Add

\frac{π}{4}

to both sides

x - \frac{π}{4} + \frac{π}{4} = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Simplify

x - \frac{π}{4} + \frac{π}{4} = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Simplify

x - \frac{π}{4} + \frac{π}{4} : x

x - \frac{π}{4} + \frac{π}{4}

Add similar elements:

- \frac{π}{4} + \frac{π}{4} = 0

= x

Simplify

π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4} : π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

= π - arcsin (\frac{7 2}{10}) + 2 πn + \frac{π}{4}

\frac{7 2}{10} = \frac{7}{5 2}

\frac{7 2}{10}

Factor

10 : 2 \cdot 5

Factor

10 = 2 \cdot 5

= \frac{7 2}{2 \cdot 5}

Cancel

\frac{7 2}{2 \cdot 5} : \frac{7}{2 \cdot 5}

\frac{7 2}{2 \cdot 5}

Apply radical rule:

2 = 2^{\frac{1}{2}}

= \frac{7 \cdot 2 ^{\frac{1}{2}}}{2 \cdot 5}

Apply exponent rule:

\frac{x ^{a}}{x ^{b}} = \frac{1}{x ^{b - a}}

\frac{2 ^{\frac{1}{2}}}{2 ^{1}} = \frac{1}{2 ^{1 - \frac{1}{2}}}

= \frac{7}{5 \cdot 2 ^{- \frac{1}{2} + 1}}

Subtract the numbers:

1 - \frac{1}{2} = \frac{1}{2}

= \frac{7}{5 \cdot 2 ^{\frac{1}{2}}}

Apply radical rule:

2^{\frac{1}{2}} = 2

= \frac{7}{5 2}

= \frac{7}{2 \cdot 5}

= π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Could not simplify further

= π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

x = arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}, x = π - arcsin (\frac{7}{5 2}) + 2 πn + \frac{π}{4}

Show solutions in decimal form

x = 1.42889 \dots + 2 πn + \frac{π}{4}, x = π - 1.42889 \dots + 2 πn + \frac{π}{4}

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Frequently Asked Questions (FAQ)

What is the general solution for sin(x)-cos(x)= 7/5 ?
The general solution for sin(x)-cos(x)= 7/5 is x=1.42889…+2pin+pi/4 ,x=pi-1.42889…+2pin+pi/4