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Solve for \( \sin(2x) = \text{blank} \)

A. \(1 - 2\sin^2 x\)

B. \(2\sin x \cos x\)

C. \(\frac{1}{2}(\cos(a-b)-\cos(a+b))\)

D. \(2\sin x + 2\cos x\)

1 Answer

2 votes

Final Answer:

The solution is
\(2\sin x \cos x\), derived from the double-angle identity for sine
(\( \sin(2x) = 2\sin x \cos x\)). This matches option B, making it the correct choice. The B is correct option.

Step-by-step explanation:

The given trigonometric equation is
\( \sin(2x) \) and we need to express it in terms of known trigonometric functions. Utilizing the double-angle identity for sine,
\( \sin(2x) = 2\sin x \cos x \), we can observe that this matches option B. Therefore, the correct answer is B.

Now, let's delve into the explanation. The double-angle identity for sine is
\( \sin(2x) = 2\sin x \cos x \), a fundamental trigonometric relationship. To understand this identity, consider the angle
\(2x\) as the sum of two angles
\(x\) and
\(x\). The identity reveals a connection between the sine of
\(2x\) and the product of sine and cosine of
\(x\). This relationship is vital in simplifying expressions involving trigonometric functions.

In option A,
\(1 - 2\sin^2 x\), this is an application of the double-angle identity for cosine
(\( \cos(2x) = 1 - 2\sin^2 x \)), not for sine. Option C introduces the sum and difference identities for cosine, which are not directly related to the given equation. Option D combines sine and cosine but lacks the double-angle form present in the original equation. By recognizing and applying the appropriate trigonometric identity, we arrive at the correct solution:
\(2\sin x \cos x\), as stated in option B. Therefore option B is correct.

User Dilavar Malek
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