<p>If (a+b)^1/2=(a-b)^-1/2, which of the following must be true?</p>
<p>(A) b=0
(B) a+b=1
(C) a-b=1
(D) a^2+b^2=1
(E) a^2-b^2=1</p>
<p>Answer is, (E)</p>
<p>Can anyone explain this? Thx in advance.</p>
<p>so (a+b)^1/2= 1/(a-b)^1/2
then you square both sides and get
a+b = 1/(a-b)
multiply both sides by (a-b) to get
a^2 +ab-ab-b^2=1
which is a^2-b^2=1</p>
<p>ahh, thanks juzam</p>
<p>wow, thats difficult to think of</p>
<p>Its not really difficult if you see it on paper because reformating problems for the computer makes them look harder than they are.</p>