213 - The Friendship Algorithm
Aired January 19, 2009

The Friendship Algorithm

Sheldon wants to use the university's grid computer for his research, but access to the computer is controlled by Barry Kripke who apparently favors his friends. Sheldon decides to befriend Kripke, but struggles from a lack of experience in making friends. Treating this like any other scientific inquiry, Sheldon studies up and develops a friendship algorithm.

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Guest Stars: John Ross Bowie as Barry Kripke, Will Deutsch as Jeremy, Jane Galloway Heitz as Mildred, Jade Zdanow as Rebecca

Writers: Bill Prady (Story), Richard Rosenstock (Story), Chuck Lorre (Teleplay), Steven Molaro (Teleplay)

Director: Mark Cendrowski

Viewers: 11 million Households Rating: 5.4/9 Adults 18-49 Rating: 4/10

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Episode Notes

  • The title references Sheldon's algorithm for making friends.

> Sheldon's Knock

Sheldon uses his knock when he goes to Penny's apartment to hand her a friendship questionnaire.

Quotes (20)

Sheldon: A fear of heights is illogical. A fear of falling, on the other hand, is prudent and evolutionary.

Wolowitz: *After he fixed Sheldon's algorithm* Gee, why can't Sheldon get a friend?

Sheldon: That's where I sit.
Barry Kripke: Ooh, you have a special spot. What kind of wacko are you?

Sheldon: What part of an inverse tangent approaching an asymptote don't you understand?

Sheldon: "Barney Bunny has two daddies now." Probably something about homosexual rabbits.


Sheldon needs time on the university's open science grid computer and learns that Barry Kripke controls access and gives his friends preferential treatment. Sheldon sets out to befriend Barry so he can use the grid computer. After Sheldon's calls to Kripke fail, he decides to learn more about friendship making and fine tune his process.

Sheldon goes to a book store to try find a guide to making friends. He finds "Stu the Cockatoo is New at the Zoo" in the children's section, where he starts talking to a young girl. Leonard pulls him away from the store before he gets into trouble. The guys arrive at the apartment and find Sheldon has finished his "Friendship Algorithm" based on the book. Sheldon calls Kripke and attempts to find a suitable interest of Kripke's that they can share, but when Sheldon gets stuck in a loop, Howard must add a loop counter and an exit to the Least Objectionable Activity.

After Sheldon and Kripke decide they will go rock climbing together, Sheldon studies up on rock climbing - on the Internet of course. While climbing with Kripke, Sheldon realizes he has a fear of falling and seizes up, just "hanging there like a big salami". Back at the apartment, Kripke joins the gang for dinner. When Sheldon changes the subject to the grid computer, Kripke explains he has no control over the access list. With no further use for his friendship, Sheldon kicks Kripke out of his friendship circle.

Comments (19)

Gordon New Zealand, 02:37 Jun 5 2014.
Mega-lol! Thought it would be something like that, after I learned what an asymptote was! I was actually watching every episode from the official broadcasted pilot to the season 7 finale in anticipation for season 8 when I heard the word "Asymptote" and wanted to know what it meant!
Tracy United States, 00:20 Apr 13 2014.
Sheldon means he feels like he's never going to reach the top of the wall he's climbing. The graph of an inverse tangent function is a curved line, sort of like a stretched out letter S. Imagine that the top of the S and the bottom of the S go on forever, each getting closer and closer to an imaginary border (the 2 asymptotes) above the S and below the S. The S never touches those borders, though. It just gets closer and closer to each of the 2 asymptotes, but it never actually touches either asymptote. It's actually a very clever piece of dialog on the part of the writers.
meera Philippines, 02:05 May 27 2013.
"an inverse tangent function that is approaching an asymptote" meant stuck. try watching the episode again.
BIG FAN Netherlands, 17:41 Mar 12 2013.
the algorithm misses one thing in the start, "Obtain Phonenumer"...
Sheldon Lee cooper United Kingdom, 11:45 Feb 6 2013.
i love TBBT
anonymous United States, 20:31 Oct 3 2012.
whoever said inverse tangent functions don't have asymptotes is an idiot
big bang theory fan United Kingdom, 13:15 Sep 12 2012.
i really want to try and faint at the top of a climbing wall .it looks real fun! :) lol!
Jack Sweden, 17:41 Feb 25 2011.
@boredofstudying say hi to arctan, which has 2 asymptotes
weirddude Guyana, 00:17 Jul 13 2010.
the prt wen sheldon tried to get make friends with the little girl was the funniest
boredofstudying Australia, 08:32 May 6 2010.
In this episode, Sheldon says "I feel like an inverse tangent function approaching an asymptote!"; this does not make sense since inverse tangent functions do not have asymptotes (there are no values for x such that tan(infinity)=x); reciprocal tangent functions have asymptotes (for y=1/tan(x), when x=0, y is undefined).

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