Finding the length of the parametric curve _=cos(_), _=sin(_) from _=0 to _=¹/2, using the formula for arc length of a parametric curve. Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/ap-calculus-bc/bc-applications-definite-integrals/bc-arc-length/e/arc-length-of-functions-in-one-variable?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusBC Watch the next lesson: https://www.khanacademy.org/math/ap-calculus-bc/bc-applications-definite-integrals/bc-vol-cross-sections/v/volume-solid-semicircle-cross-section?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusBC Missed the previous lesson? https://www.khanacademy.org/math/ap-calculus-bc/bc-applications-definite-integrals/bc-arc-length/v/parametric-curve-arc-length?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusBC AP Calculus BC on Khan Academy: Learn AP Calculus BC - everything from AP Calculus AB plus a few extra goodies, such as Taylor series, to prepare you for the AP Test ... https://www.youtube.com/watch?v=F3KyoI26fKI Note: All Khan Academy content is available for free at (www.khanacademy.org)

Proving that an inscribed angle is half of a central angle that subtends the same arc. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-shapes/v/right-triangles-inscribed-in-circles-proof?utm_source=YT&utm_medium=Desc&utm_campaign=highschoolmath Missed the previous lesson? https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/v/inscribed-angles-exercise-example?utm_source=YT&utm_medium=Desc&utm_campaign=highschoolmath High School Math on Khan Academy: Did you realize that the word "algebra" comes from Arabic (just like "algorithm" and "al jazeera" and "Aladdin")? And what is so great about algebra anyway? This tutorial doesn't explore algebra so much as it introduces the history and ideas that underpin it. About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world. Our resources cover preschool through early college education, including math, biology, chemistry, physics, economics, finance, history, grammar and more. We offer free personalized SAT test prep in partnership with the test developer, the College Board. Khan Academy has been translated into dozens of languages, and 100 million people use our platform worldwide every year. For more information, visit www.khanacademy.org, join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything. ... https://www.youtube.com/watch?v=MyzGVbCHh5M Note: All Khan Academy content is available for free at (www.khanacademy.org)

Is the area of a square proportional to the side length of the square? Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-ratio-proportion/cc-7th-proportional-rel/e/analyzing-and-identifying-proportional-relationships?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade Watch the next lesson: https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-ratio-proportion/cc-7th-proportional-rel/v/analyzing-and-identifying-proportional-relationships-ex3?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade Missed the previous lesson? https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-ratio-proportion/cc-7th-proportional-rel/v/proportionality-between-side-length-and-perimeter?utm_source=YT&utm_medium=Desc&utm_campaign=7thgrade ... https://www.youtube.com/watch?v=Hzz5p0qlObs Note: All Khan Academy content is available for free at (www.khanacademy.org)

Two different types of changes in the membrane potential of a neuron. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/nervous-system-introduction/v/saltatory-conduction-neurons?utm_source=YT&utm_medium=Desc&utm_campaign=healthandmedicine Missed the previous lesson? https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/nervous-system-introduction/v/correction-to-sodium-and-potassium-pump-video?utm_source=YT&utm_medium=Desc&utm_campaign=healthandmedicine Health & Medicine on Khan Academy: No organ quite symbolizes love like the heart. One reason may be that your heart helps you live, by moving ~5 liters (1.3 gallons) of blood through almost 100,000 kilometers (62,000 miles) of blood vessels every single minute! It has to do this all day, everyday, without ever taking a vacation! Now that is true love. Learn about how the heart works, how blood flows through the heart, where the blood goes after it leaves the heart, and what your heart is doing when it makes the sound “Lub Dub.” About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world. Our resources cover preschool through early college education, including math, biology, chemistry, physics, economics, finance, history, grammar and more. We offer free personalized SAT test prep in partnership with the test developer, the College Board. Khan Academy has been translated into dozens of languages, and 100 million people use our platform worldwide every year. For more information, visit www.khanacademy.org, join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything. ... https://www.youtube.com/watch?v=kY8FEq0teOs Note: All Khan Academy content is available for free at (www.khanacademy.org)