What is the general solution for (sec(x)+tan(x))/(cot(x)+cos(x))=sec^2(x) ?

The general solution for (sec(x)+tan(x))/(cot(x)+cos(x))=sec^2(x) is No Solution for x\in\mathbb{R}

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Popular Trigonometry >

(sec(x)+tan(x))/(cot(x)+cos(x))=sec^2(x)

Solution

\frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} = sec^{2} (x)

Solution

No Solution for x \in R

Solution steps

\frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} = sec^{2} (x)

Subtract

sec^{2} (x)

from both sides

\frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} - sec^{2} (x) = 0

Simplify

\frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} - sec^{2} (x) : \frac{sec ( x ) + tan ( x ) - sec ^{2} ( x ) ( cot ( x ) + cos ( x ) )}{cot ( x ) + cos ( x )}

\frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} - sec^{2} (x)

Convert element to fraction:

sec^{2} (x) = \frac{sec ^{2} ( x ) ( cot ( x ) + cos ( x ) )}{cot ( x ) + cos ( x )}

= \frac{sec ( x ) + tan ( x )}{cot ( x ) + cos ( x )} - \frac{sec ^{2} ( x ) ( cot ( x ) + cos ( x ) )}{cot ( x ) + cos ( x )}

Since the denominators are equal, combine the fractions:

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

= \frac{sec ( x ) + tan ( x ) - sec ^{2} ( x ) ( cot ( x ) + cos ( x ) )}{cot ( x ) + cos ( x )}

\frac{sec ( x ) + tan ( x ) - sec ^{2} ( x ) ( cot ( x ) + cos ( x ) )}{cot ( x ) + cos ( x )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

sec (x) + tan (x) - sec^{2} (x) (cot (x) + cos (x)) = 0

Express with sin, cos

sec (x) + tan (x) - (cos (x) + cot (x)) sec^{2} (x)

Use the basic trigonometric identity:

sec (x) = \frac{1}{cos ( x )}

= \frac{1}{cos ( x )} + tan (x) - (cos (x) + cot (x)) (\frac{1}{cos ( x )})^{2}

Use the basic trigonometric identity:

tan (x) = \frac{sin ( x )}{cos ( x )}

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

Use the basic trigonometric identity:

cot (x) = \frac{cos ( x )}{sin ( x )}

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

Simplify

\frac{1}{cos ( x )} + \frac{sin ( x )}{cos ( x )} - (cos (x) + \frac{cos ( x )}{sin ( x )}) (\frac{1}{cos ( x )})^{2} : \frac{sin ^{2} ( x ) - 1}{cos ( x ) sin ( x )}

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

Combine the fractions

\frac{1}{cos ( x )} + \frac{sin ( x )}{cos ( x )} : \frac{1 + sin ( x )}{cos ( x )}

Apply rule

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

= \frac{1 + sin ( x )}{cos ( x )}

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

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

(cos (x) + \frac{cos ( x )}{sin ( x )}) (\frac{1}{cos ( x )})^{2}

Join

cos (x) + \frac{cos ( x )}{sin ( x )} : \frac{cos ( x ) sin ( x ) + cos ( x )}{sin ( x )}

cos (x) + \frac{cos ( x )}{sin ( x )}

Convert element to fraction:

cos (x) = \frac{cos ( x ) sin ( x )}{sin ( x )}

= \frac{cos ( x ) sin ( x )}{sin ( x )} + \frac{cos ( x )}{sin ( x )}

Since the denominators are equal, combine the fractions:

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

= \frac{cos ( x ) sin ( x ) + cos ( x )}{sin ( x )}

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

(\frac{1}{cos ( x )})^{2} = \frac{1}{cos ^{2} ( x )}

(\frac{1}{cos ( x )})^{2}

Apply exponent rule:

(\frac{a}{b})^{c} = \frac{a ^{c}}{b ^{c}}

= \frac{1 ^{2}}{cos ^{2} ( x )}

Apply rule

1^{a} = 1

1^{2} = 1

= \frac{1}{cos ^{2} ( x )}

= \frac{cos ( x ) sin ( x ) + cos ( x )}{sin ( x )} \cdot \frac{1}{cos ^{2} ( x )}

Multiply fractions:

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

= \frac{( cos ( x ) sin ( x ) + cos ( x ) ) \cdot 1}{sin ( x ) cos ^{2} ( x )}

(cos (x) sin (x) + cos (x)) \cdot 1 = cos (x) sin (x) + cos (x)

(cos (x) sin (x) + cos (x)) \cdot 1

Multiply:

(cos (x) sin (x) + cos (x)) \cdot 1 = (cos (x) sin (x) + cos (x))

= (cos (x) sin (x) + cos (x))

Remove parentheses:

(a) = a

= cos (x) sin (x) + cos (x)

= \frac{cos ( x ) sin ( x ) + cos ( x )}{cos ^{2} ( x ) sin ( x )}

Factor out common term

cos (x)

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

Cancel the common factor:

cos (x)

= \frac{sin ( x ) + 1}{sin ( x ) cos ( x )}

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

Least Common Multiplier of

cos (x), sin (x) cos (x) : cos (x) sin (x)

cos (x), sin (x) cos (x)

Lowest Common Multiplier (LCM)

Compute an expression comprised of factors that appear either in

cos (x)

sin (x) cos (x)

= cos (x) sin (x)

Adjust Fractions based on the LCM

Multiply each numerator by the same amount needed to multiply its

corresponding denominator to turn it into the LCM

cos (x) sin (x)

For

\frac{1 + sin ( x )}{cos ( x )} :

multiply the denominator and numerator by

sin (x)

\frac{1 + sin ( x )}{cos ( x )} = \frac{( 1 + sin ( x ) ) sin ( x )}{cos ( x ) sin ( x )}

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

Since the denominators are equal, combine the fractions:

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

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

Expand

(1 + sin (x)) sin (x) - (sin (x) + 1) : sin^{2} (x) - 1

(1 + sin (x)) sin (x) - (sin (x) + 1)

= sin (x) (1 + sin (x)) - (sin (x) + 1)

Expand

sin (x) (1 + sin (x)) : sin (x) + sin^{2} (x)

sin (x) (1 + sin (x))

Apply the distributive law:

a (b + c) = ab + a c

a = sin (x), b = 1, c = sin (x)

= sin (x) \cdot 1 + sin (x) sin (x)

= 1 \cdot sin (x) + sin (x) sin (x)

Simplify

1 \cdot sin (x) + sin (x) sin (x) : sin (x) + sin^{2} (x)

1 \cdot sin (x) + sin (x) sin (x)

1 \cdot sin (x) = sin (x)

1 \cdot sin (x)

Multiply:

1 \cdot sin (x) = sin (x)

= sin (x)

sin (x) sin (x) = sin^{2} (x)

sin (x) sin (x)

Apply exponent rule:

a^{b} \cdot a^{c} = a^{b + c}

sin (x) sin (x) = sin^{1 + 1} (x)

= sin^{1 + 1} (x)

Add the numbers:

1 + 1 = 2

= sin^{2} (x)

= sin (x) + sin^{2} (x)

= sin (x) + sin^{2} (x)

= sin (x) + sin^{2} (x) - (sin (x) + 1)

- (sin (x) + 1) : - sin (x) - 1

- (sin (x) + 1)

Distribute parentheses

= - (sin (x)) - (1)

Apply minus-plus rules

+ (- a) = - a

= - sin (x) - 1

= sin (x) + sin^{2} (x) - sin (x) - 1

Add similar elements:

sin (x) - sin (x) = 0

= sin^{2} (x) - 1

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

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

\frac{- 1 + sin ^{2} ( x )}{cos ( x ) sin ( x )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

- 1 + sin^{2} (x) = 0

Solve by substitution

- 1 + sin^{2} (x) = 0

Let:

sin (x) = u

- 1 + u^{2} = 0

- 1 + u^{2} = 0 : u = 1, u = - 1

- 1 + u^{2} = 0

Move

1

to the right side

- 1 + u^{2} = 0

Add

1

to both sides

- 1 + u^{2} + 1 = 0 + 1

Simplify

u^{2} = 1

u^{2} = 1

For

x^{2} = f (a)

the solutions are

x = f (a), - f (a)

u = 1, u = - 1

1 = 1

1

Apply rule

1 = 1

= 1

- 1 = - 1

- 1

Apply rule

1 = 1

= - 1

u = 1, u = - 1

Substitute back

u = sin (x)

sin (x) = 1, sin (x) = - 1

sin (x) = 1, sin (x) = - 1

sin (x) = 1 : x = \frac{π}{2} + 2 πn

sin (x) = 1

General solutions for

sin (x) = 1

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}

x = \frac{π}{2} + 2 πn

x = \frac{π}{2} + 2 πn

sin (x) = - 1 : x = \frac{3 π}{2} + 2 πn

sin (x) = - 1

General solutions for

sin (x) = - 1

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}

x = \frac{3 π}{2} + 2 πn

x = \frac{3 π}{2} + 2 πn

Combine all the solutions

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

Since the equation is undefined for:

\frac{π}{2} + 2 πn, \frac{3 π}{2} + 2 πn

No Solution for x \in R

Graph

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Frequently Asked Questions (FAQ)

What is the general solution for (sec(x)+tan(x))/(cot(x)+cos(x))=sec^2(x) ?
The general solution for (sec(x)+tan(x))/(cot(x)+cos(x))=sec^2(x) is No Solution for x\in\mathbb{R}