Difference between revisions of "1993 IMO Problems/Problem 2"

(Created page with "Let <math>D</math> be a point inside acute triangle <math>ABC</math> such that <math>\angle ADB = \angle ACB+\frac{\pi}{2}</math> and <math>AC\cdot BD=AD\cdot BC</math>. \rene...")
 
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\renewcommand{\theenumi}{\Alph{enumi}}
 
\renewcommand{\theenumi}{\Alph{enumi}}
 
\begin{enumerate}
 
\begin{enumerate}
\item Calculate the ratio \frac{AC\cdot CD}{AC\cdot BD}
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\item Calculate the ratio <math>\frac{AC\cdot CD}{AC\cdot BD}</math>
 
\item Prove that the tangents at <math>C</math> to the circumcircles of <math>\triangle ACD</math> and <math>\triangle BCD</math> are perpendicular.
 
\item Prove that the tangents at <math>C</math> to the circumcircles of <math>\triangle ACD</math> and <math>\triangle BCD</math> are perpendicular.
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\end{enumerate}

Revision as of 10:34, 21 November 2017

Let $D$ be a point inside acute triangle $ABC$ such that $\angle ADB = \angle ACB+\frac{\pi}{2}$ and $AC\cdot BD=AD\cdot BC$. \renewcommand{\theenumi}{\Alph{enumi}} \begin{enumerate} \item Calculate the ratio $\frac{AC\cdot CD}{AC\cdot BD}$ \item Prove that the tangents at $C$ to the circumcircles of $\triangle ACD$ and $\triangle BCD$ are perpendicular. \end{enumerate}