Search found 9 matches

by bobmarksdale
Fri Aug 07, 2009 4:44 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0620: "Wings"
Replies: 141
Views: 36648

Re: "Wings" Discussion

He'd only fall at .88 m/s/s so it wouldn't hurt *that* bad unless he pulled the bricks almost all the way up to the pulley to start with so he could fly really high, which seems silly for a 1st try experiment.
by bobmarksdale
Wed Sep 03, 2008 4:06 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0471: "Aversion Fads"
Replies: 522
Views: 68593

Re: "Aversion Fads" Discussion

Alt Text:

"Hey, are you friends with any hamsters? This kite needs a passenger."

Update first post?
by bobmarksdale
Fri Aug 22, 2008 4:12 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0466: "Moving"
Replies: 165
Views: 32643

Re: Moving

Nice, my network is called linsksys... my username for setup is admin... any guesses as to what the password is? is it "root"? When I go to my grandparents I have to hang out in their bathroom if I need internet because the range on the neighbor's network only extends to that section of t...
by bobmarksdale
Mon Jun 09, 2008 4:14 am UTC
Forum: Logic Puzzles
Topic: Convergent Series
Replies: 3
Views: 1616

Re: Convergent Series

No. By the Cauchy-Schwartz inequality, (sum 1/a_k)*(sum a_k/k 2 ) >= (sum 1/k) 2 . Since the right hand side diverges, at least one of the terms on the left hand side diverges. I don't know about that law/theorum, but I'll accept it as true. It just seemed way too easy to be...
by bobmarksdale
Mon Jun 09, 2008 2:08 am UTC
Forum: Logic Puzzles
Topic: Convergent Series
Replies: 3
Views: 1616

Convergent Series

I'm not exactly sure if it's logic or math, but I saw this problem on the wall when I went to take the SAT (math department at a state university). Find a series a k such that these two series both converge. http://img518.imageshack.us/img518/5674/picture6ck8.th.png This is easy enough. Just use a k...
by bobmarksdale
Mon May 19, 2008 4:25 am UTC
Forum: Logic Puzzles
Topic: The Sum of all Digits Between One and One Million
Replies: 28
Views: 10221

Re: The Sum of all Digits Between One and One Million

I'm pretty sure that's not the right answer. the sum of 0-9 digits is 45. Now, 0-9 shows up in the ones digit place 100,000 times, in the tens digit place 10,000 times, hundreds 1,000 times, etc. So 45*(111,111) + 1 = 4,999,996. I'm pretty sure that's not the right answer. Consider the numb...
by bobmarksdale
Sun May 18, 2008 3:05 am UTC
Forum: Logic Puzzles
Topic: The Sum of all Digits Between One and One Million
Replies: 28
Views: 10221

Re: The Sum of all Digits Between One and One Million

@ST47: Yeah, that was my interpretation of the question too. The solution to that puzzle is look at each digit. As you range from 1 to 1,000,000 each digit spends one tenth of its time being each of the possibilities, and the millions digit adds one to the total. So its the number of digits, 6, tim...
by bobmarksdale
Sun May 18, 2008 2:30 am UTC
Forum: Logic Puzzles
Topic: Simple? Math
Replies: 3
Views: 1933

Re: Simple? Math

x * y = x - y
x * y + y = x
y * ( x + 1 ) = x
y = x / ( x + 1)

so:
Spoiler:
0 = 0 / 1
1/2 = 1 / 2
-1 = (-1/2)/(1/2)
and there are infinitely more solutions, such as:
(x,y)
(2,2/3)
(3,3/4)
(4,4/5)
etc...
by bobmarksdale
Wed Jan 16, 2008 3:41 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0370: "Redwall"
Replies: 155
Views: 35106

Re: "Redwall" discussion

Speaking of recycled plots...

Image

Go to advanced search