Is (1+tan^2(x))cos^2(x)=1 ?

The answer to whether (1+tan^2(x))cos^2(x)=1 is True

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prove (1+tan^2(x))cos^2(x)=1

prove

(1 + tan^{2} (x)) cos^{2} (x) = 1

True

Solution steps

(1 + tan^{2} (x)) cos^{2} (x) = 1

Manipulating left side

(1 + tan^{2} (x)) cos^{2} (x)

Express with sin, cos

(1 + tan^{2} (x)) cos^{2} (x)

Use the basic trigonometric identity:

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

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

Simplify

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

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

Apply exponent rule:

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

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

Join

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

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

Convert element to fraction:

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

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

Since the denominators are equal, combine the fractions:

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

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

Multiply:

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

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

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

Multiply fractions:

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

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

Cancel the common factor:

cos^{2} (x)

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

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

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

Rewrite using trig identities

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

Use the Pythagorean identity:

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

= 1

= 1

We showed that the two sides could take the same form

\Rightarrow True

\frac{1 - sin ( θ )}{cos ( θ )} = sec (θ) - tan (θ)

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

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

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

\frac{1 + cos ( 4 x )}{2} = cos^{2} (2 x)

Is (1+tan^2(x))cos^2(x)=1 ?
The answer to whether (1+tan^2(x))cos^2(x)=1 is True