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function F

by success1111 » Wed May 13, 2009 8:41 am
if the function F is defined by F(x)=x^2+1/x^2 for all nonzero numbers X, then F(-1/X)=

A. –1/f(x)
B. 1/f(x)
C. 1-f(x)
D. –f(x)
E. f(x)
Trust but verify.
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Re: function F

by Vemuri » Wed May 13, 2009 8:45 am
success1111 wrote:if the function F is defined by F(x)=x^2+1/x^2 for all nonzero numbers X, then F(-1/X)=

A. –1/f(x)
B. 1/f(x)
C. 1-f(x)
D. –f(x)
E. f(x)
IMO E. The function converts back to the expression of F(x)
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by scoobydooby » Wed May 13, 2009 8:47 am
F(-1/X)= (replacing xby -1/x in f(x) we get
=>(-1/x)^2+1/(-1/x)^2
=>1/x^2+x^2
=f(x)

hence, E
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Re: function F

by success1111 » Wed May 13, 2009 9:24 am
Vemuri wrote:
success1111 wrote:if the function F is defined by F(x)=x^2+1/x^2 for all nonzero numbers X, then F(-1/X)=

A. –1/f(x)
B. 1/f(x)
C. 1-f(x)
D. –f(x)
E. f(x)
IMO E. The function converts back to the expression of F(x)
OA is E
Trust but verify.
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