Help please (i pressed 0.09 by mistake)
2 answers:
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You need to know the properties of each function.
Tan is opposite (y) over adjacent (x). Sin>0 means that sin is positive, therefore, it is located on either quadrant 1 or 2. Tan=4/3 so it is located in quadrant 1.
The side of the triangle must be Adjacent=3 opposite=4 and hypotenuse=5
Now, you are asked to find the half angle of Cos which is
By following the formula, cos=3/5 then:
Multiply everything (inside the square 
root) by 5
Then just simplify
The answer is Square root of 20 over 5
Tan is opposite (y) over adjacent (x). Sin>0 means that sin is positive, therefore, it is located on either quadrant 1 or 2. Tan=4/3 so it is located in quadrant 1.
The side of the triangle must be Adjacent=3 opposite=4 and hypotenuse=5
Now, you are asked to find the half angle of Cos which is
By following the formula, cos=3/5 then:
Answer:
- 150° and 210°
- 0
Step-by-step explanation:
It is convenient to memorize the trig functions of the "special angles" of 30°, 45°, 60°, as well as the way the signs of trig functions change in the different quadrants. Realizing that the (x, y) coordinates on the unit circle correspond to (cos(θ), sin(θ)) can make it somewhat easier.
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<h3>20.</h3>You have memorized that cos(x) = (√3)/2 is true for x = 30°. That is the reference angle for the 2nd-quadrant angle 180° -30° = 150°, and for the 3rd-quadrant angle 180° +30° = 210°.
Cos(x) is negative in the 2nd and 3rd quadrants, so the angles you're looking for are
150° and 210°
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<h3>Bonus</h3>You have memorized that sin(π/4) = √2/2, and that cos(3π/4) = -√2/2. The sum of these values is ...
√2/2 + (-√2/2) = 0
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<em>Additional comments</em>
Your calculator can help you with both of these problems.
The coordinates given on the attached unit circle chart are (cos(θ), sin(θ)).
