Two times the sum of a number and 7
1 answer:
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Answer:
°
Step-by-step explanation:
The law of sines is a property of all triangles that relates the sides and angles of a triangle. This property states the following:
Where side (A) is the side opposite angle (<a), side (B) is the side opposite angle (<b), and side (C) is the property opposite angle (<c).
Substitute each of the sides and respective angles into the formula, and solve for the unknown angle (<x). Please note that a triangle with two congruent sides (referred to as an isosceles triangle) has a property called the base angles theorem. This states that the angles opposite the congruent sides in an isosceles triangle are congruent. Therefore, there can be two (<x)'s in this triangle.
One can shorten the equation so it only holds the parts that will play a role in solving this equation,
Now take the cross product in this equation to simplify it further,
Inverse operations, solve this equation for (x),
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)).
