Question

What is the value of 1 – 2sin^2(105°)?

Answer 1

Answer:

Step-by-step explanation:

1-2sin²∝=cos 2∝

1-2sin²(105)=cos(2×105)

=cos 210

=cos (180+30)

=-cos 30

$=-\frac{\sqrt{3}}{2}$

Answer 2

The correct answer is option A which is the value of the expression is -√3/2.

What is trigonometry?

The branch of mathematics sets up a relationship between the sides and the angles of the right-angle triangle termed trigonometry.

The expression will be solved as:-

1-2sin²∝=cos 2∝

1-2sin²(105)=cos(2×105)

1-2sin²(105=cos 210

1-2sin²(105=cos (180+30)

1-2sin²(105=-cos 30

1-2sin²(105 = -√3/2.

Therefore the correct answer is option A which is the value of the expression is -√3/2.

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