Menu Close

given-f-x-y-ax-bxy-cy-for-x-y-R-2-proof-that-if-a-c-1-then-f-x-y-f-y-x-x-y-is-f-x-y-bounced-




Question Number 272 by 123456 last updated on 25/Jan/15
given f(x,y)=ax+bxy+cy for (x,y)∈R^2   proof that if ∣a−c∣≤1 then ∣f(x,y)−f(y,x)∣≤∣x−y∣  is f(x,y) bounced?
givenf(x,y)=ax+bxy+cyfor(x,y)R2proofthatifac∣⩽1thenf(x,y)f(y,x)∣⩽∣xyisf(x,y)bounced?
Answered by prakash jain last updated on 18/Dec/14
f(x,y)−f(y,x)=ax+bxy+cy−ay−bxy−cx  =(a−c)x−(a−c)y=(a−c)(x−y)  ∣f(x,y)−f(y,x)∣=∣(a−c)(x−y)∣=∣a−c∣∣x−y∣  Since ∣a−c∣≤1  ∣f(x,y)−f(y,x)∣≤∣x−y∣  f(x,y) is not bounded.
f(x,y)f(y,x)=ax+bxy+cyaybxycx=(ac)x(ac)y=(ac)(xy)f(x,y)f(y,x)∣=∣(ac)(xy)∣=∣ac∣∣xySinceac∣⩽1f(x,y)f(y,x)∣⩽∣xyf(x,y)isnotbounded.