SOLUTION: solve: {{{t^(1/2)-4t^(1/4)+4=0}}}

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Question 351405: solve: t%5E%281%2F2%29-4t%5E%281%2F4%29%2B4=0
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
t%5E%281%2F2%29-4t%5E%281%2F4%29%2B4=0
The easiest solution for this equation is found by noticing that the exponent of t%5E%281%2F2%29 is twice as large as the exponent of t%5E%281%2F4%29. This makes this equation in quadratic form for t%5E%281%2F4%29. So we can solve this as a quadratic equation.

To make this a little clearer, I am going to employ a temporary variable. Let q+=+t%5E%281%2F4%29. This makes q%5E2+=+%28t%5E%281%2F4%29%29%5E2+=+t%5E%282%2F4%29+=+t%5E%281%2F2%29 and substituting these into the equation we get:
q%5E2+-+4q+%2B+4+=+0
This is obviously a quadratic equation. We can solve this using factoring (or the Quadratic Formula). This factors pretty easily:
%28q-2%29%28q-2%29+=+0
or
%28q-2%29%5E2+=+0
By the Zero Product Property we know that this (or any) product can be zero only if one of its factors is zero. Since we only have one distinct factor:
q - 2 = 0
or
q = 2
This is a solution for our temporary variable, q. To find the solution for t we can replace q with t%5E%281%2F4%29:
t%5E%281%2F4%29+=+2
Raise each side to the 4th power gives:
t = 16

We can check our answer by substituting 16 for t in the original equation:
t%5E%281%2F2%29-4t%5E%281%2F4%29%2B4=0
%2816%29%5E%281%2F2%29-4%2816%29%5E%281%2F4%29%2B4=0
4+-+4%282%29+%2B+4+=+0
4 - 8 + 4 = 0
0 = 0 Check!

Note: After you have done a few problems like this, you will not need to use a temporary variable. You will see how to go directly from:
t%5E%281%2F2%29-4t%5E%281%2F4%29%2B4=0
to
%28t%5E%281%2F4%29+-+2%29%28t%5E%281%2F4%29+-+2%29+=+0
to
t%5E%281%2F4%29+-+2+=+0
to
t%5E%281%2F4%29+=+2+
to
t = 16