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Old November 5th, 2009, 01:52 AM
purebladeknight purebladeknight is offline
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the age of a machine,x, in years is related to the probability of breakdown,y, by the formula

x=3 + ln( y/1-y)

determine the probability of breakdown for 1,3,10 years!

i am fairly sure 1st i take away the 3 from both sides thus leaving x-3=ln(y/1-y).

then inverse of ln makes y/1-y=e^x-3?
yes, now multiply both sides by 1-y, and move the ye^x-3 to the left and factorise out the y and then divide both sides by e^x-3

y= (1-y) (e^x-3)

y=e^x-3 - y e^x-3

y + y e^x-3=e^x-3

y(1 + e^x-3)=e^x-3

y=e^x-3/(1 + e^x-3)

now you got y by itself.

sub in those values of x to get probabilty.

it seems correct but correct me if im wrong

Last edited by mr fantastic; November 5th, 2009 at 04:11 AM. Reason: Added quote tags.
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