【高校　数学Ⅰ】　数と式７７　命題の逆·裏　（１５分）

Watch all the lessons from Try's talented instructors for free! Try IT video lessons for junior high and high school students are designed to be easy to understand! You can use them to prepare and review for school, as well as for regular tests and exam preparation. The lessons are taught by top instructors with plenty of teaching experience, who are known for their fun and easy-to-understand teaching methods. *This lesson is a video created during the old curriculum. *Please be careful when watching it to prepare for entrance exams or regular tests for the new curriculum. If you watch the video and think, "It's easy to understand!" or "I want to take a class like this!", Try's individual instruction may be right for you. For details on Try's individual instruction service, to request materials, or to contact us, please click here. https://bit.ly/4hjhKSE In addition, +‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥+ Try offers free video lessons, "Try IT," to support home learning. "Try IT" can be used free of charge even by non-members. Please use it to prepare for exams and improve your home study. Video Lessons Try IT Official Website here: https://bit.ly/4jLULBg +‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥+ In this video lesson, you can learn "High School Mathematics I: Numbers and Formulas 77: The Inverse of Propositions" in about 15 minutes. The key to solving the problem is that "even if the original proposition is true, its inverse is not necessarily true." Please watch the video lesson in the following order: [Points] ⇒ [Examples] ⇒ [Practice] ⇒ [Summary]. If you have any questions about a unit other than this one, please click on the URL below. You can watch the video lessons for each unit together. ■If you have any questions about "Mathematics I," click here! ・Mathematics I Numbers and formulas https://goo.gl/kkMY1W ・Mathematics I Expanding equations https://goo.gl/qgCjRb ・Mathematics I Factorization and cross-relationships https://goo.gl/Ae70Kr ・Mathematics I Rational numbers, irrational numbers, square roots https://goo.gl/VyO7Rv ・Mathematics I Equations and inequalities https://goo.gl/omHWxP ・Mathematics I Absolute value and equations https://goo.gl/wv1T4f ・Mathematics I Quadratic equations https://goo.gl/tyqgHp ・Mathematics I Sets https://goo.gl/uPzTs3 ・Mathematics I Propositions and necessary and sufficient conditions https://goo.gl/9uT75D ・Mathematics I Graphs of quadratic functions ht tps://goo.gl/sDgXo1 ・Mathematics I Maximum and minimum of quadratic functions https://goo.gl/fIsO2s ・Mathematics I Application of quadratic functions https://goo.gl/b4WFAW ・Mathematics I Common points of parabolas and straight lines https://goo.gl/igr3ek ・Mathematics I Quadratic inequalities https://goo.gl/21RZov ・Mathematics I Trigonometric ratios https://goo.gl/q0cers ・Mathematics I Sine theorem and cosine theorem https://goo.gl/W44zp2 ・Mathematics I Application to area and volume https://goo.gl/UPRHnx ・Mathematics I Data dispersion and correlation https://goo.gl/4JhqPf ■If you have any questions about "Mathematics A", click here! ・Mathematics A Sets and complements https://goo.gl/uB9WnZ ・Mathematics A Number of cases (tree diagrams, summation rules, product rules) https://goo.gl/OS72Rb ・Mathematics A Permutations https://goo.gl/liNVCE ・Mathematics A Circular permutations and duplicate permutations https://goo.gl/8EQcDC ・Mathematics A Combinators nCr https://goo.gl/EVfHms ・Mathematics A: Use of combinations https://goo.gl/vk57MX ・Mathematics A: Grouping https://goo.gl/qOYVj4 ・Mathematics A: Probability https://goo.gl/dhyIIV ・Mathematics A: Probability: Summation and complementary events https://goo.gl/3hQORr ・Mathematics A: Probability: Dice and independent trials https://goo.gl/Vfi70n ・Mathematics A: Probability: Dice and repeated trials https://goo.gl/ZCPe iC ・Mathematics A Probability Lottery・Multiplication Theorem https://goo.gl/UJSHxY ・Mathematics A Properties of Integers https://goo.gl/of491x ・Mathematics A Prime Factorization https://goo.gl/7ptLnq ・Mathematics A Multiples and Divisors・Relatively Prime https://goo.gl/nGkFLS ・Mathematics A Integer Solutions to Equations https://goo.gl/7C4xXf ・Mathematics A Integer Solutions to Equations Quotient and Remainder of Division https://goo.gl/BVW8MA ・Mathematics A Euclidean Algorithm and linear indeterminate equations https://goo.gl/ycG6An ・Mathematics A Fractions and decimals https://goo.gl/tqQTjF ・Mathematics A N-ary system https://goo.gl/kt3HVR ・Mathematics A Properties of interior and exterior divisions of lines and parallel lines https://goo.gl/fqLumM ・Mathematics A Bisectors of angles of triangles https://goo.gl/RncX40 ・Mathematics A Circumcenter, Incenter, and Centroid of a triangle https://goo.gl/IhYU3e ・Mathematics A Ceva-Menelaus theorem https://goo.gl/pq6m0Y ・Mathematics A: Theorem of circular angles and inscribed tangents https://goo.gl/uRoms0 ・Mathematics A: Tangents to circles, tangent theorem, square power theorem https://goo.gl/MPJ...