Discover new information and get your questions answered with IDNLearn.com. Join our knowledgeable community to find the answers you need for any topic or issue.
Sagot :
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.
__
20.
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°
__
Bonus
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
_____
Additional comments
Your calculator can help you with both of these problems.
The coordinates given on the attached unit circle chart are (cos(θ), sin(θ)).
We value your participation in this forum. Keep exploring, asking questions, and sharing your insights with the community. Together, we can find the best solutions. Thank you for choosing IDNLearn.com. We’re committed to providing accurate answers, so visit us again soon.