Unit Circle Problems solve cosW=sin20, sinW=cos(-10), sinW< 0.5 and 1<tanW

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Discussion Overview

The discussion revolves around solving unit circle problems involving trigonometric equations and inequalities, specifically focusing on finding angles \( W \) that satisfy the equations \( \cos W = \sin 20 \), \( \sin W = \cos(-10) \), and the inequalities \( \sin W < 0.5 \) and \( 1 < \tan W \). The scope includes theoretical understanding and graphical representation of trigonometric functions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant asks for all solutions for \( W \) between 0 and 360 degrees, inclusive, and requests supporting diagrams.
  • Another participant emphasizes the importance of understanding the unit circle, noting that \( x = \cos(\theta) \) and \( y = \sin(\theta) \), and questions where \( \sin(20) \) is located on the circle.
  • A participant acknowledges their understanding of the unit circle and identifies that \( \cos(70) = \sin(20) \), but expresses uncertainty about how to proceed with the inequalities.
  • Another participant suggests using graphs of \( y = \sin(x) \) and \( y = \tan(x) \) to analyze the inequalities, providing specific angles where \( \sin(x) = 1/2 \) and \( \tan(x) = 1 \).

Areas of Agreement / Disagreement

Participants generally agree on the relevance of the unit circle and the need for graphical analysis, but there is no consensus on how to proceed with the inequalities or the specific solutions for \( W \).

Contextual Notes

Some participants express limitations in their ability to share diagrams, and there are unresolved steps regarding the inequalities and how to apply the unit circle effectively to find all solutions.

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Without a calculator, find all solutions w between 0 and 360, inclusive, providing diagrams that support your results.

1) cosW=sin20

2) sinW=cos(-10)

3) sinW< 0.5

4) 1<tanW
 
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You titled this "unit circle problems". Have you drawn a unit circle? Do you know that, at each (x, y) point on the circle, x= cos(\theta) and y= sin(\theta)? Where is sin(20) on that circle? So for what angle is cos(W)= sin(20)?
 
yes I am aware that y= sin(theta) and x= cos(theta)
and yes I drew my unit circle
so sin20 is in the first quadrant but I am not sure how to import images here, if possible
and cos70= sin 20, I figured that out a few days ago, however I am stuck on 3 and 4
 
Instead of using a unit circle, for 3 and 4, draw the graphs of y= sin(x) and y= tan(x). Compare the graph of y= sin(x) with the graph of y= 1/2 and compare the graph of y= tan(x) with y= 1. You should know that sin(x)= 1/2 for \pi/6 radians (30 degrees) and 5\pi/6 radians (150 degrees) and that tan(x)= 1 for \pi/4 radians (45 degrees) and 5\pi/4 radians (225 degrees). (There is a nice graphing app at https://www.desmos.com/calculator.)
 

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