Is 2cos^2(A)-cos(2A)-1=0 ?

The answer to whether 2cos^2(A)-cos(2A)-1=0 is True

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

prove 2cos^2(A)-cos(2A)-1=0

prove

2 cos^{2} (A) - cos (2 A) - 1 = 0

True

Solution steps

2 cos^{2} (A) - cos (2 A) - 1 = 0

Manipulating left side

2 cos^{2} (A) - cos (2 A) - 1

Rewrite using trig identities

2 cos^{2} (A) - cos (2 A) - 1

Use the Double Angle identity:

2 cos^{2} (x) - 1 = cos (2 x)

= - cos (2 A) + cos (2 A)

Add similar elements:

- cos (2 A) + cos (2 A) = 0

= 0

= 0

We showed that the two sides could take the same form

\Rightarrow True

p ro v e \frac{cot ( x ) + 1}{cos ( x ) + sin ( x )} = csc (x)

p ro v e csc (A) = \frac{7}{4}

p ro v e \frac{sin ^{2} ( x )}{sin ^{2} ( x )} = sin (x)

p ro v e csc (cos (+ sin (x))) = cot (+ 1)

p ro v e 4 sin (\frac{x}{2}) cos (\frac{x}{2}) = 2 sin (x)