Olympiad Geometry
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What's New?

version 1.4 [19.09.2020]

  • added new chapters:
    • Phantom Points (Chapter 11)
    • Isogonal Lines (Chapter 24)
      • Isogonal Conjugates (Section 24.1)
      • Isogonal Lines Lemma (Section 24.2)
      • Parallelogram Isogonality Lemma (Section 24.3)
    • Apollonian Circles (Chapter 26)
  • added new sections:
    • Angle measure of an arc (page 38)
    • Ptolemy's Theorem (Section 10.7)
    • Fermat Points (Section 10.9)
    • Pappus' Theorem (Section 15.4)
    • Pole-Polar Duality (Section 21.1)
  • added a link to an AoPS forum for discussing the unsolved problems from this book
  • added new properties in different chapters (Properties 10.3.4, 10.4.3, 25.2.6)
  • added 24 new solved examples in Chapters 1-5 for better onboarding experience
  • added 52 new unsolved problems (exact list at the end of the book)
  • reordered the Chapters for better learning experience
  • minor:
    • added more elementary proofs for the properties in Section 19.1
    • added a more beautiful proof of Property 10.3.1
    • added an alternate proof of Property 10.6.1
  • technical:
    • corrected the wrong usage of Example instead of Property in many places
    • corrected the wrong usage of opening quotation marks in LaTeX
    • fixed equations that were split in two lines in a paragraph

version 1.3 [21.09.2018]

  • added new sections in the chapter "Inversion" (18.1 sqrt(bc) Inversion and 18.2 sqrt(bc/2) Inversion)
  • added a new chapter about Mixtilinear & Curvilinear Incircles (Chapter 17)
  • added a new chapter about Spiral Similarity (Chapter 21)
  • added 50 new unsolved problems (exact list at the end of the book)

version 1.2 [28.07.2018]

  • added 50 new unsolved problems (exact list at the end of the book)
  • added a new section in the chapter "A Few Useful Lemmas" (10.9 HM Point)
  • added a new well-known lemma (Example 16.3 Midpoint of the altitude)
  • added a new approach for proving Collinearity (8.2 Parallelogram Trick)
  • added a new approach for proving Concurrence (9.4 Concurrent Perpendiculars)
  • added a solved example with 4 different proofs in the chapter Symmedian (Example 15.1)
  • added visual mnemonic for remembering the ratios in Menelaus' / Ceva's Theorem and the intersections in Pascal Theorem
  • restructured the chapters a bit, now the book can roughly be divided in two parts:
    Junior (first 10 chapters) and Senior (the other 12 chapters)

version 1.1 [01.07.2018]

  • added 44 new unsolved problems (exact list at the end of the book)
  • added a new well-known property in the chapter "A Few Useful Lemmas"
  • added a few new solved examples in the chapter "Angles of a Transversal"
  • fixed minor mistakes and typos

version 1.0.0 [01.09.2016]

© Stefan Lozanovski, 2016-2022
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