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The angle \theta_1θ 1 ​ theta, start subscript, 1, end subscript is located in Quadrant \text{I}Istart text, I, end text, and \sin(\theta_1)=\dfrac{1}{2}sin(θ 1 ​ )= 2 1 ​ sine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis, equals, start fraction, 1, divided by, 2, end fraction . What is the value of \cos(\theta_1)cos(θ 1 ​ )cosine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis?

User Alex Fu
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2 Answers

2 votes

Answer:

60/61

Explanation:

60/61

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User Hellium
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6.8k points
1 vote

Answer:

√3/2

Explanation:

Given an angle θ₁ located on in the first quadrant and sinθ₁ = 1/2, we are required to calculate the value of cosθ₁.

Firstly, we need to find the value of the angle θ₁ from the expression sinθ₁ = 1/2.

Given sinθ₁ = 1/2

Take the arcsin of both sides

arcsin(sinθ₁) = arcsin(1/2)

The arcsin will cancel out the sin at the left hand side to have only θ₁. Hence;

θ₁ = arcsin(1/2)

Using the calculator, θ₁ = 30°

Since we are to find the value of cosθ₁

cosθ₁ = cos30°

cos30° = √3/2

Hence the value of cosθ₁ is √3/2

User Harry Johnston
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