#math - Sat 12 May 2007 between 00:01 and 00:12

NY Lost Funds



TRWBWSmad2: so there is a formula for the altitude of the triangle, double check me, is it h^2=w*(S-w) in this case?
Smad2yeah
mkfurst, what are you stuck on?
TRWBWSmad2: okay, so i think you also have, from the right triangle thing, that h^2+(w-S/2)^2=(S/2)^2
fursti will show you my dumbshit work... some of it
http://www.flickr.com/photos/55714008@N00/494286181/
TRWBWSmad2: and i haven't done it out, but i think that's enough equations in h and w and S to show it.
Smad2: well anyway that's my hint
mkfurst, what you need to do is use two different relationships against each other to cancel H out
furstwell the volume one h=4pi^2/r^2
mkok
Smad2how'd you get that last equation, which triangle were you working on
mkyou can solve the cost one for h too
furstin that screenshot i gave u
mkit's solved for t, not h
furstis the next line to be 0=0.16pir^2+0.04pirh-t ?
mkyep, and that = 0
Borg7could someone tell me how to calculate RMSPE (root mean squared percentage error)?
mkso now bring the block with h over to the other side
TRWBWSmad2: is it true that the distance from the midpoint of the hypoteneus of a right triangle to the vertex of the right angle is always one half the length of hypotenues?
Smad2yeah
mk(if anyone could correct 'block' to the proper mathematical term that'd be great)
(term?)
appletizerBorg7, take the average sum of squared errors, square root it and express it in percentage form
TRWBWSmad2: well that's what i'm using, that S/2 is half the hypoteneus of the triangle ABC
Jafetmk: Expression?
mk0 = ab+cd, what cd is
Smad2ah i see now :)
TRWBWSmad2: that is, take M to be the midpoint of AB, then you have a right triangle with MCE, where E is where the altitiude hits AB
mkis that an expression?
Borg7appletizer: well i think that is just wrong
TRWBWSmad2: like i said i only did it until i got enough equations that i thought it should be solvable. but then, you asked for a "hint". might work, might not.
Borg7appletizer: the percentage applies to each error
fursti'm just not doing the algebra correctly http://www.flickr.com/photos/55714008@N00/494258006/
Smad2:) let me try
appletizerBorg7, ah yes you're right sorry
error expressed as percentage
etc etc
the rest's the same
Borg7yeah i need to write a little matlab function for it

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NY Lost Funds