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

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

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

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

prove

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

True

Solution steps

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

Manipulating left side

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

Expand

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

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

Apply Perfect Square Formula:

(a + b)^{2} = a^{2} + 2 ab + b^{2}

a = 1, b = tan (x)

= 1^{2} + 2 \cdot 1 \cdot tan (x) + tan^{2} (x)

Simplify

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

1^{2} + 2 \cdot 1 \cdot tan (x) + tan^{2} (x)

Apply rule

1^{a} = 1

1^{2} = 1

= 1 + 2 \cdot 1 \cdot tan (x) + tan^{2} (x)

Multiply the numbers:

2 \cdot 1 = 2

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

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

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

Manipulating right side

sec^{2} (x) + 2 tan (x)

Rewrite using trig identities

sec^{2} (x) + 2 tan (x)

Use the Pythagorean identity:

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

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

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

We showed that the two sides could take the same form

\Rightarrow True

\frac{sec ^{2} ( x )}{2 tan ( x )} = csc (2 x)

\frac{cot ( x )}{sec ( x )} = csc (x) - sin (x)

cot^{2} (x) (sec^{2} (x) - 1) = 1

2 cos (x) - 2 cos^{3} (x) = sin (x) sin (2 x)

sec (x) + tan (x) = \frac{1}{sec ( x ) - tan ( x )}

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