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If cos 30 = root 3/2, find the value of sin15

1 Answer

6 votes

Answer:

To find the value of sin 15, we can use the half-angle formula for sine:

sin (θ/2) = ±√[(1 - cos θ)/2]

where θ is the angle in radians.

In this case, we want to find sin 15, which is half of 30. So we can write:

sin 15 = sin (30/2)

Using the half-angle formula for sine with θ = 30, we have:

sin 15 = ±√[(1 - cos 30)/2]

We are given that cos 30 = √3/2, so we can substitute this value into the formula:

sin 15 = ±√[(1 - √3/2)/2]

To simplify this expression, we can rationalize the denominator by multiplying both the numerator and denominator by √2:

sin 15 = ±√[(√2 - √6)/4]

Since 0° < 15° < 90°, the sine of 15 degrees is positive. So we can take the positive square root:

sin 15 = √[(√2 - √6)/4]

Therefore, the value of sin 15 is:

sin 15 = √[(√2 - √6)/4]

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User Ewen
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