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Find the value of `(tan 9^(@)+cot9^(@))/(tan27^(@)+cot27^(@))`. |
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Answer» Correct Answer - `(3+sqrt(5))/(2)` `(tan9^(@)+cot9^(@))/(tan27^(@)+cot27^(@))=(tan9^(@)+(1)/(tan9^(@)))/(tan27^(@)+(1)/(tan27^(@)))` `=(Tan^(2)9^(@)+1)/(2 tan 9^(@))(2tan 27^(@))/((tan^(2)27^(@)+1)` `=(sin 54^(@))/(sin18^(@))=(cos 36^(@))/(sin18^(@))` `=(sqrt(5)+1)/(4).(4)/(sqrt(5)-1)` `=(sqrt(5)+1)/(sqrt(5)-1)xx(sqrt(5)+1)/(sqrt(5)+1)=(3+sqrt(5))/(2)`. |
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