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#1 Re: Help Me ! » trigonometric equations » 2009-07-30 15:02:43
thank you very much
sorry for the delayed reply as i haven't logged in for a while
baskar:)
#2 Re: Exercises » trigonometri problem » 2009-06-07 15:08:47
answer for (1) find the value of cos^2 (18) + cos^2 (54):
cos^2 (18) = [10+2 sqrt(5)]/16 = 0.9045085
we know cos3x = 4cos^3 (x) - 3cos(x)
=> cos(54) = 4 cos^3 (18) - 3cos(18) = 4 (0.74001063) - 3 (0.9045085)
=> cos(54) = 2.96004252 - 2.71352550 = 0.24651702
=> cos^2 (54) = (0.24651702)^2 = 0.06077
=> cos^2 (18) + cos^2 (54) = 0.9045085 + 0.0607700 = 0.9652785
cheers, baskar
#3 Help Me ! » trigonometric equations » 2009-06-07 14:41:02
- baskar
- Replies: 3
dear friends,
i need a solution for this sum 
the smallest positive root of the equation tanx-x=0 lies in
(a) (0,pi/2) (b) (pi/2,pi)
(c) (pi,3pi/2) (d) (3pi/2,2pi)
please help me.
thanks
bhaskar
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