<p>Its on BB page 373 number 3. Theres a thread concerning it but i still have a question.</p>
<p>if x+ 1/x= 2 then whats the value of x^2 + 1/x^2 ? answer is 2.</p>
<p>I got 4, which is wrong. Heres what i did.</p>
<p>i turned X+ 1/ X = 2 into x^2+1/x = 2</p>
<p>And then x^2+1/x^2 into x^4+1/x^2 </p>
<p>The second is the square of the first, so its 4. which is wrong. My question is : Why DOESN'T this method work?</p>
<p>I am a little confused by your method.
But...I think all you need to do is multiply each side of the original equation by x to get 2x = x =1 and then you solve for x and plug it into the second equation.</p>
<p>
[quote]
i turned X+ 1/ X = 2 into x^2+1/x = 2
[/quote]
do you mean multiply both sides by x? you're not being fair if you only multiply x by x, but not 1/x by x or 2 by x.</p>
<p>
[quote]
And then x^2+1/x^2 into x^4+1/x^2
[/quote]
squaring the term (x^2 + 1/x^2) DOES NOT give you (x^4 + 1/x^2)</p>
<p>This was easy.I got in without even having to use paper</p>
<p>x + (1/x)= 2 then whats the value of (x^2) + (1/x^2)</p>
<p>x + (1/x)= 2
x^2 + 1 = 2x
x^2 - 2x + 1 = 0
(x-1)^2=0
x=1</p>
<p>(x^2) + (1/x^2)
=(1^2) + (1/1^2)
=1+1
=2</p>
<p>the 2nd isnt actually the square of the first
[x + (1/x)]^2
=x^2 + 2 + (1/x^2)</p>