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domi1989
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#1
Report Thread starter 12 years ago
#1
I need some help with this question

Giving your answers in terms of pi, solve the equation

3tan^2 θ -1=0

for θ in the interval -pi<θ<pi

thanks
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meef cheese
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tan2x = 1/3
tanx = +/- 1/sqrt3
x = pi/6, -5pi/6, -pi/6, 5pi/6
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domi1989
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Report Thread starter 12 years ago
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how did you get?

x = pi/6, -5pi/6, -pi/6, 5pi/6
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steve2005
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(Original post by domi1989)
how did you get?

x = pi/6, -5pi/6, -pi/6, 5pi/6
Use a 2 by 2 by 2 equilateral triangle - them half to get angles 30, 60 and 90. Frrom this tan 30 = 1/rt3

360/12 =30 therefore 2pi/12 = pi/6

Now use the CAST circle. Tangent is positive in 1st and 3rd quadrants and negative in 2nd and 4th.

SORRY for making the WRONG correction. I hope it is now ALL correct
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Malik
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(Original post by steve2005)
Use a 2 by 2 by 2 equilateral triangle - them half to get angles 30, 60 and 90. Frrom this tan 30 = 1/rt3

360/12 =30 therefore 2pi/12 = pi/6

Now use the CAST circle. Tangent is positive in 1st and 3rd quadrants and negative in 2nd and 4th.
Long time no see Steve, tan30=1/rt3 that angle in your diagram is for angle of 60degrees.
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steve2005
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#6
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Hi typing error.... now corrected.
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