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Question 443343: What are all the positive angles Q in degree for which cos Q = square root 3/2?
Answer by swincher4391(1107)   (Show Source):
You can put this solution on YOUR website! Think about your 30º, 60º, 90º triangle.
Draw a right triangle with angles 30 and 60 to make this easier.
In a 30,60,90
The side opposite the 30º is the shortest side, and it is 1.
The side opposite the 60º is length 
The side opposite the 90º is the hypotenuse (longest side) and it is 2.
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I really wish I had a picture to make this easier.
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Try this http://www.google.com/imgres?imgurl=http://www.biology.arizona.edu/BioMath/tutorials/Trigonometric/graphics/trig_30_60_90.gif&imgrefurl=http://www.biology.arizona.edu/BioMath/tutorials/Trigonometric/specialangles.html&h=268&w=393&sz=2&tbnid=0lxAXKWR0X3n7M:&tbnh=85&tbnw=124&prev=/search%3Fq%3D30%2B60%2B90%2Btriangle%26tbm%3Disch%26tbo%3Du&zoom=1&q=30+60+90+triangle&hl=en&usg=__7SUm2hzMWNJUh7c0LUs3K-ybbsY=&sa=X&ei=uM-9TdvSEdKGtwf75ti0BQ&ved=0CC4Q9QEwBQ
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Anyway, if you know sin(x) = opp/hypo, cos(x) = adj/hypo, tan(x) = opp/hypo, then let's practice.
cos(60)? Locate the 60º, Find the adjacent and hypotenuse sides. You have 1/2. So cos(60) = 1/2
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So now that we know how to do it, locate the angle that has adjacent side and hypotenuse 2. That's 30º
But are we done?
Remember
Q1 = All
Q2 = Sin
Q3 = Tangent
Q4 = Cosine
(All Students Take Classes)
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This tells us where each trig function is positive.
We look and see that in Q1 and Q4 cos is positive.
Locate the angle that lays on the x-axis. This is 360º. Then 360º - 30º = 330º, which is our other angle.
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