doubleangle

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    Double-angle Formulae

    Having some trouble with this one. Can anyone help me out? Many thanks. Q. Given that \tan 2A=\frac{2\tan A}{1-\tan^2 A}, find \tan\,22.5^{\circ} in surd form. Attempt: \tan2(22.5)=\frac{2\tan22.5}{1-\tan^222.5} tan45=\frac{2\tan22.5}{1-\tan^222.5} 1(1-\tan^222.5)=2\tan22.5...
  2. P

    Multiple Choice Problem on Using Double-Angle Formulas

    Hi, I've been trying to solve this question, and I just can't get an answer that looks like one of the choices given. Could anyone walk me through the question or give me a hint that might lead me to the right answer? Thank you very much! The question is: Use double-angle formulas to rewrite...