tan2x*cotx - 3 = 0
We know
that: tan2x = sin2x/cos2x and cotx = cosx/sinx
==>
sin2x/cos2x *cosx/sinx = 3
Now we know that sin2x =
2sinx*cosx
==> 2sinxcosx/cos2x * cosx/sinx =
3
Reduce sinx:
==>
2cos^2 x/ cos2x = 3
Now we know that cos2x = 2cos^2
x-1
==> 2cos^2 x/(2cos^2 x -1) =
3
==> 2cos^2 x = 3(2cos^2 x
-1)
==> 2cos^2 x = 6cos^2 x -
3
==> -4cos^2 x=
-3
==> 4cos^2 x =
3
==> cos^2 x =
3/4
==> cosx = +-sqrt3/
2
==> x = pi/6, 5pi/6, 7pi/6, and
11pi/6
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