marasofia1616
Find the point on the terminal side of θ =3pie/4 that has a y coordinate of 1. Show your work for full credit.
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tjones89
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|dw:1350326762097:dw|
tjones89
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the goal is to find the coordinates of the point at the end of that angle. We are told that y = 1 at that point so we just need to find the x coordinate and we're set
tjones89
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to do this we use the triangle that is made when you draw a line straight down from the point like I have in the drawing
tjones89
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we know the length of that side is one because we were told that y = 1
tjones89
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now if we knew the angle inside that triangle we could use the tangent function to find the length of the adjacent side, which I labelled x.
tjones89
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any idea how we can find it?
marasofia1616
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tan 3pi/4=1/x?
tjones89
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nope, you used the wrong angle, we need to find the angle inside that triangle
tjones89
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|dw:1350328078591:dw|
tjones89
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the 3pi / 4 is outside the triangle
marasofia1616
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If I use the Unit Circle and says that 3pi/4 is 135... and I am looking for that inside angle I get that it is equal to 45.
tjones89
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right, so now we can use tangent to find x
\[\tan(45) = \frac{ 1 }{ x }\]
tjones89
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isolate x and you've got it
marasofia1616
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x=-1?
tjones89
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yep!
marasofia1616
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got it... thanks!
lbouskila
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how is x= -1?
AG1997
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So the point would be (-1, 1)?