![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
asher553The weather was unsettled today, pleasant enough for a morning walk of about a half-hour, but mostly a good day to spend the Sabbath indoors reading in bed, and that's what I did.
Spent a good chunk of the day getting re-acquainted with Stewart's Calculus (9th ed.). I've been reviewing the first two chapters, on limits and introducing the derivative. My win for the day was solving one of the related-rates problems (problem 27 on p. 173) without recourse to pencil and paper. (A camera, located 4000 feet from the launch pad, is tracking a rocket that's rising at 600 ft/s and is conveniently at 3000 ft altitude - so, a 3-4-5 triangle, and the rocket is 5000 ft from the camera. We want the speed the rocket is moving away from the camera (dz/dt), so it's just like the problem with the two cars on p. 171 except it's easier because the camera isn't moving and dx/dt disappears. We get dz/dt = (y/z)(dy/dt), that's 3/5 of 600 and you can do that in your head, it's 360 - which is indeed the correct answer. So, yay me.)
In the Torah readings, we started the book of Exodus this Sabbath, and this coming week's reading will continue with G-d's revelation to Moses, and the beginning of the plagues on Egypt. Meanwhile, Daf Yomi (Bava Kamma 65) deals with the valuation of a stolen article. I've been keeping up with the Daf more-or-less regularly via Real Clear Daf on my mobile phone.
Having a get-together with a few friends tomorrow and looking forward to that.
Spent a good chunk of the day getting re-acquainted with Stewart's Calculus (9th ed.). I've been reviewing the first two chapters, on limits and introducing the derivative. My win for the day was solving one of the related-rates problems (problem 27 on p. 173) without recourse to pencil and paper. (A camera, located 4000 feet from the launch pad, is tracking a rocket that's rising at 600 ft/s and is conveniently at 3000 ft altitude - so, a 3-4-5 triangle, and the rocket is 5000 ft from the camera. We want the speed the rocket is moving away from the camera (dz/dt), so it's just like the problem with the two cars on p. 171 except it's easier because the camera isn't moving and dx/dt disappears. We get dz/dt = (y/z)(dy/dt), that's 3/5 of 600 and you can do that in your head, it's 360 - which is indeed the correct answer. So, yay me.)
In the Torah readings, we started the book of Exodus this Sabbath, and this coming week's reading will continue with G-d's revelation to Moses, and the beginning of the plagues on Egypt. Meanwhile, Daf Yomi (Bava Kamma 65) deals with the valuation of a stolen article. I've been keeping up with the Daf more-or-less regularly via Real Clear Daf on my mobile phone.
Having a get-together with a few friends tomorrow and looking forward to that.
