Question on domain of combined function

• Diruga Vejida

  31 Aug 09, 19:50

  F(x) = sqrt ( x-2 )

  G(x) = sqrt (x-4)

  Is the Domain of F(x).G(x) just  x >/= 4, or is X </= 2 also part of the domain?

   

  Thanks in advance.

• TenSaru

  31 Aug 09, 22:21

  x>/=4 ... for x<4 G(x) will not exist

• eagle

  31 Aug 09, 22:33

  remember that you cannot square root a negative number and get a real number :)

• wee_ws

  1 Sep 09, 08:26

  Originally posted by Diruga Vejida:

  F(x) = sqrt ( x-2 )

  G(x) = sqrt (x-4)

  Is the Domain of F(x).G(x) just  x >/= 4, or is X </= 2 also part of the domain?

   

  Thanks in advance.

  Hi,

    I presume you are considering the product of F and G?

    In that case, we take the intersection of both domains (i.e. x >= 2 and x >= 4).

    Thanks!

  Cheers,
  Wen Shih