Meet the 94-year-old calculus teacher! @ycmathematicsphysicsandche5659 @blackpenredpen

Uploaded May 2024 | Updated September 2026, 2 weeks ago

Thanks to the YouTube algorithm, I discovered Mr. Feng, a 94-year-old calculus teacher, @ycmathematicsphysicsandche5659 . He said in his note that teaching makes him happy and makes his life meaningful, which I resonate with so much. I want to make a video to introduce him to you! Please consider subscribing to his channel and supporting what he does. Thank you.
The solution to the derivative challenge problem: youtu.be/V9rrLp2CpPw?si=SadRcaYGZUVruIuj

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Big thanks to my Patrons for the full-marathon support!
Ben D, Grant S, Erik S. Mark M, Phillippe S. Michael Z, Nicole D.

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Meet the 94-year-old calculus teacher! @ycmathematicsphysicsandche5659

Trig & Precalculus Office Hours w/ @blackpenredpen - Were Live, Ask Away!

Math for fun: solving (4^x+8)^4-(8^x-4)^4=(4+8^x+4^x)^4

Pythagorean Theorem & Its Inverse (my favorite proof)

The most fun way of solving this quartic equation

Solving an AIME functional equation (how do we guess a solution)

$100 integrals part 2 (EXTREME PASSION!) 100 integrals part 2! Including integration by parts, u-substitution, trig substitution, partial fraction decomposition, reverse power rule for integrals, integral reduction formulas, Weierstrass substitution, improper integrals, special functions, Feynmans technique of integration, integration with power series, the Gaussian Integral, double integrals, Jacobian, polar coordinate, change the order of integration, and more! Get the file & answer key on my Patreon 👉 https://www.patreon.com/posts/102752235 100 integrals (original) 👉 https://youtu.be/dgm4-3-Iv3s Thanks to Nathaniel Barnett for the time stamps! 0:00 100 integrals part 2! Q1, 0:00:46 integral of 2022 Q2, 0:03:03 integral by trig identities and u-sub Q3, 0:08:23 integral by trig sub Q4, 0:12:34 integral by u-sub and integration by parts Q5, 0:17:02 Q6, 0:19:42 Q7, 0:30:07 Q8, 0:33:45 Q9, 0:37:58 Q10, 0:45:16 Q11, 0:48:30 Q12, 0:53:16 Q13, 0:59:06 Q14, 0:58:34 Q15, 1:00:41 Q16, 1:04:56 Q17, 1:07:27 Q18, 1:12:27 Q19, 1:14:42 Q20, 1:18:50 Q21, 1:22:30 integral of x^n*e^x Q22, 1:25:14 integral of (ln(x))^n Q23, 1:27:40 integral of sin^n(x) Q24, 1:37:44 integral of tan^n(x) Q25, 1:42:58 integral of sec^n(x) Q26, 1:52:14 Q27, 1:54:45 Q28, 1:57:45 Q29, 2:01:49 Q30, 2:04:49 Q31, 2:24:38 integral of sec(x) by Weierstrass Substitution Q32, 2:27:17 Q33, 2:31:25 Q34, 2:35:00 Q35, 2:37:20 Q36, 2:42:02 Q37, 2:44:24 Q38, 2:50:18 Q39, 2:51:53 Q40, 2:56:12 Q41, 3:00:21 Q42, 3:04:07 Q43, 3:06:45 Q44, 3:11:58 Q45, 3:19:02 Q46, 3:24:19 Q47, 3:28:36 Q48, 3:31:54 Q49, 3:33:44 Q50, 3:43:40 Q51, 3:49:16 Q52, 3:55:44 Q53, 3:59:50 Q54, 4:03:18 integral of x/(1+e^x) Q55, 4:08:21 integral of e^x/(1+x) Q56, 4:09:21 integral of e^e^x Q57, 4:10:27 integral of ln(ln(x)) Q58, 4:12:40 Q59, 4:14:28 Q60, 4:19:48 integral of the Lambert W function Q61, 4:25:39 improper integral of 1/x^p from 1 to inf Q62, 4:28:52 Q63, 4:29:32 Q64, 4:32:55 Q65, 4:35:29 the Gaussian Integral Q66, 4:50:04 Q67, 4:55:42 Q68, 4:58:36 integral of ln(x) from 0 to 1 Q69, 5:02:56 Q70, 5:10:32 Q71, 5:13:24 integral of ln(x)/(x-1) from 0 to 1 Q72, 5:21:08 integral of (x-1)/ln(x) from 0 to 1 Q73, 5:28:08 integral by symmetry Q74, 5:34:14 integral by even and odd function properties Q75, 5:43:16 Q76, 5:51:17 Q77, 5:52:58 Q78, 6:00:28 the Dirichlet integral, the integral of sin(x)/x from 0 to inf Q79, 6:08:10 Q80, 6:13:28 Q81, 6:37:48 double integral & change the order of integration Q82, 6:45:45 Q83, 6:49:24 Q84, 6:54:00 Q85, 6:57:25 Q86, 7:03:50 Q87, 7:07:33 Q88, 7:11:11 Q89, 7:17:27 Q90, 7:21:37 Q91, 7:28:52 Q92, 7:37:47 Q93, 7:55:15 Q94, 8:07:00 Q95, 8:10:24 Q96, 8:21:05 Q97, 8:22:55 Q98, 8:26: 30 Q99, 8:29: 59 Q100, 8:33:33 Q101, 8:38:32 the BIG integral from the Berkeley Math Tournament$

This is how HKDSE asked a logarithm question (Hong Kong university entrance exam)

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Meet the 94-year-old calculus teacher! @ycmathematicsphysicsandche5659