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6. Find the positive integers p, q, r, s satisfying `tan (pi/24)=(sqrt(p)-sqrt(q))(sqrt(r)-(s))`A. 6B. 7C. 8D. 9 |
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Answer» Correct Answer - C Using `tan 2A = (2 tan A)/(1-tan^(2)A)` `tan 7.5^(@)=(sin 15^(@))/(1+cos 15^(@))` `=(sin 15^(@))/(1+cos 15^(@))xx(1-cos 15^(@))/(1-cos 15^(@))` `=(sin 15^(@)(1-cos 15^(@)))/(sin^(2)15^(@))` `=(1-cos 15^(@))/(sin 15^(@))` `=(1-(sqrt(3)+1)/(2sqrt(2)))/((sqrt(3)-1)/(2sqrt(2)))` `=(2sqrt(2)-sqrt(3)-1)/(sqrt(3)-1)` `=(2sqrt(2)-sqrt(3)-1)/(sqrt(3)-1)xx(sqrt(3)+1)/(sqrt(3)+1)` `=((2sqrt(2)-sqrt(3)-1)(sqrt(3)+1))/(3-1)` `=(2sqrt(6)+2sqrt(2)-4-2sqrt(3))/(2)` `=(2(sqrt(6)+sqrt(2)-2-sqrt(3)))/(2)` `=sqrt(3)(sqrt(2)-1)-sqrt(2)(sqrt(2)-1)` `= (sqrt(3)-sqrt(2))(sqrt(2)-1)` |
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