A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 3 years ago
MIT 18.01 David Jerison talks about a symmetry shortcut in the first lecture. he says its basically switching what we call the axis, tring to find the x and y intercept, wouldnt this just get the same point just calling it something else? is there a name for this trick or something i could search to understand whats happening better
anonymous
 3 years ago
MIT 18.01 David Jerison talks about a symmetry shortcut in the first lecture. he says its basically switching what we call the axis, tring to find the x and y intercept, wouldnt this just get the same point just calling it something else? is there a name for this trick or something i could search to understand whats happening better

This Question is Open

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0he starts talking about it at 31 min in.

Stacey
 3 years ago
Best ResponseYou've already chosen the best response.0Can you give a link to the lecture?

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0At 35min he explains the reason. I think the function y=1/x is very special as y=1/x and x=1/y. The symmetry here means the computing process of yintercept is totally the same as for xintercept, so if you get the xintercept is 2x0, then yintercept must be 2y0. So he used the shortcut. But it doesn't mean the point is same as you can see y0=1/x0, the xintercept is 2x0, the yintercept is 2y0=2/x0. They're different points. Hope this answer your question. If it's very hard to understand, you can use the common method to compute the yintercept to understand the trick.

anonymous
 3 years ago
Best ResponseYou've already chosen the best response.0The function is y = 1/x, so multiply both sides by x and we get xy = 1. Now divide both sides by y and we now have x = 1/y. So the x and they y are interchangeable. It is a special property of this function. That's also why he can say in the end that 2x0y0 = 2. From algebraic manipulation above we saw that xy = 1 and x and y can refer to any point on the function graph, including x0y0 then 2x0y0 must equal 2xy which is 2(1) hitch is 2. To see that we are not just renaming things, suppose the function was y = 2x. Dividing both sides by x gives y/x = 2. Now divide by y and you get 1/x = 2/y. Multiply by x^2 and you get x =( 2x^2)/y. Clearly x and y are not symmetrical here.
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.