66
kaymant
·2009-09-17 03:25:20
If f(0)=0 or f(1)=1, we are done. So WLOG, lets assume that f(0)>0 and f(1)<1. Now, consider the function
g(x) = f(x) - x.
Obviously, g is continuous in the interval [0,1]. Further,
g(0)=f(0)-0 >0 and
g(1)=f(1)-1 <0
Hence, by intermediate value theorem, there exists some x in the interval (0,1) such that g(x)=0 which means that f(x)=x.
24
eureka123
·2009-09-17 03:41:52
how did u assume f(0)>0 and f(1)<1
and g(x) = f(x) - x.
I mean why this only and not something else........
anyways soln is rally good
1
RAY
·2009-09-17 06:30:59
intermediate value theorem???
24
eureka123
·2009-09-17 07:05:19
the intermediate value theorem states that for each value between the least upper bound and greatest lower bound of the image of a continuous function there is a corresponding value in its domain mapping to the original.
1
A
·2009-09-18 05:13:13
Actually Eureka , the max value of f(x) is 1 .... f(1)-1 can be equal to or less than 0. If it's equal then we have already found a solution ... so we assume it 's less than 0.same for the other case... @ rohit As for intermediate value theorem ref. to calculus by Maron... it's very handy....