Is 2sin^2(3x)+cos(6x)=1 ?

The answer to whether 2sin^2(3x)+cos(6x)=1 is True

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prove 2sin^2(3x)+cos(6x)=1

prove

2 sin^{2} (3 x) + cos (6 x) = 1

True

Solution steps

2 sin^{2} (3 x) + cos (6 x) = 1

Manipulating left side

2 sin^{2} (3 x) + cos (6 x)

Rewrite using trig identities

2 sin^{2} (3 x) + cos (6 x)

Use the Double Angle identity:

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

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

= cos (6 x) - (cos (2 \cdot 3 x) - 1)

cos (6 x) - (cos (2 \cdot 3 x) - 1) = 1

cos (6 x) - (cos (2 \cdot 3 x) - 1)

Multiply the numbers:

2 \cdot 3 = 6

= cos (6 x) - (cos (6 x) - 1)

- (cos (6 x) - 1) : - cos (6 x) + 1

- (cos (6 x) - 1)

Distribute parentheses

= - (cos (6 x)) - (- 1)

Apply minus-plus rules

- (- a) = a, - (a) = - a

= - cos (6 x) + 1

= cos (6 x) - cos (6 x) + 1

Add similar elements:

cos (6 x) - cos (6 x) = 0

= 1

= 1

= 1

We showed that the two sides could take the same form

\Rightarrow True