Question 135913: find all exact solutions of the equation:
2sinx+1=0
Answer by nycsharkman(136)   (Show Source):
You can put this solution on YOUR website! Find all exact solutions of the equation:
2sinx + 1 = 0
A trig equation will have exactly ONE ANSWER for each inverse function you use to solve it; an answer in exact form provides only those restricted range angles, nothing more.
Back to your question.
Treat this like a regular linear equation. Do not allow the sine function to confuse you.
Subtract 1 from both sides.
Doing so, we get this:
2sinx = -1
Divide both sides by 2.
sinx = -(1/2)
In the unit circle, we are given two answers for sinx = -(1/2).
x = 210 degrees AND 330 degrees
Is this clear?
NOTE: Trig will be much more pleasant if you take time out to memorize the unit circle degree and radian measures.
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