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May 3rd, 2018, 02:49 AM  #1 
Newbie Joined: May 2018 From: UK Posts: 2 Thanks: 0  find the possible values of sin theta if cos theta = 2/3
Hello 1. Find the possible values of sin theta if: a. Cos theta = 2/3 b. cos theta =  3/sq13 Can someone explain the steps to take to find the values of the above? I have looked online and was not able to get a clear understanding what is needed to get the values which will help me with my exam next month. Thank you very much. 
May 3rd, 2018, 05:02 AM  #2 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,958 Thanks: 1146 Math Focus: Elementary mathematics and beyond 
By Pythagoras, $\sin^2\theta+\cos^2\theta=1$, so a) $\sin\theta=\pm\sqrt{1\cos^2\theta}$. Use known values to complete the calculation. You can employ a similar method for b). 
May 3rd, 2018, 05:09 AM  #3 
Newbie Joined: May 2018 From: UK Posts: 2 Thanks: 0 
Thank you.


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2 or 3, cos, find, sin, theta, values 
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