Question 29984: the graph of y=tanA intersects the graph of y = -1 at?
what is an intercept of y=3sin2x?
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! y=tanA asking where is tanA=-1?
First, find where tanA=+1, since your calculator stores this value. You get A = 45degrees.
So, where is tan -ve? Answer is in the second and fourth quadrants, so we need the equivalent angle there:
180-45 --> 135degrees
360-45 --> 315degrees
These are the 2 answers within the 0 to 360 degree range.
2. y = 3sin2x
--> 3sin2x = 0
sin2x = 0
2x = 0 or 180 or 360 or 540 or 720
--> x = 0 or 90 or 180 or 270 or 360
These are the 5 answers within the 1 to 360 degree range.
Look at my Lesson on solving Trig equations to understand my method, if you are not sure.
Jon.
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