Question 496098: Find the solutions 18cot2x - 6 = 0 in the interval from 0 to two pi inclusive.
a) pi/3, 2pi/3, 4pi/3, 5pi/3
b) pi/4, 3pi/4, 5pi/4, 7pi/4
c) pi/6, 5pi/6, 7pi/6, 11pi/6
d) pi/4, pi/2, 2pi/3, 5pi/6
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Find the solutions 18cot2x - 6 = 0 in the interval from 0 to two pi inclusive.
a) pi/3, 2pi/3, 4pi/3, 5pi/3
b) pi/4, 3pi/4, 5pi/4, 7pi/4
c) pi/6, 5pi/6, 7pi/6, 11pi/6
d) pi/4, pi/2, 2pi/3, 5pi/6
**
18cot^2x - 6 = 0
18cot^2x=6
cot^2x=6/18=1/3
cotx=1/√3=√3/3
ans:
x=π/3 and 4π/3 (does not include 2π/3 and 5π/3 because cot is negative in these quadrants)
none of given answers completely correct, answer (a) only half correct.
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