How can the rationalized numerator be simplified?

  • Thread starter r0bHadz
  • Start date
In summary, the conversation is about finding the correct answer for the equation \frac {\sqrt{2x+3}+1}4 and how to simplify it to \frac {x+1}{2(\sqrt{2x+3}-2)}. The solution involves multiplying by the conjugate, simplifying, and discussing a possible typo in the original equation.
  • #1
r0bHadz
194
17

Homework Statement


[itex] \frac {\sqrt{2x+3}+1}4 [/itex]

Homework Equations

The Attempt at a Solution


[itex] \frac {\sqrt{2x+3}+1}4 [/itex] * [itex] \frac {\sqrt{2x+3}-1}{\sqrt{2x+3}-1} [/itex] = [itex] \frac {2x+3-1}{4\sqrt{2x+3}-4}[/itex] = [itex] \frac {2x+2}{4\sqrt{2x+3}-4} [/itex] = [itex] \frac {2(x+1)}{2(2\sqrt{2x+3}-2)} [/itex] = [itex]\frac {x+1}{2\sqrt{2x+3} -2} [/itex]

but doc. Lang is telling me the answer is [itex]\frac {x+1}{2(\sqrt{2x+3}-2)} [/itex]

How did he come to this result??
 
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  • #2
r0bHadz said:

Homework Statement


[itex] \frac {\sqrt{2x+3}+1}4 [/itex]

Homework Equations

The Attempt at a Solution


[itex] \frac {\sqrt{2x+3}+1}4 [/itex] * [itex] \frac {\sqrt{2x+3}-1}{\sqrt{2x+3}-1} [/itex] = [itex] \frac {2x+3-1}{4\sqrt{2x+3}-4}[/itex] = [itex] \frac {2x+2}{4\sqrt{2x+3}-4} [/itex] = [itex] \frac {2(x+1)}{2(2\sqrt{2x+3}-2)} [/itex] = [itex]\frac {x+1}{2\sqrt{2x+3} -2} [/itex]

but doc. Lang is telling me the answer is [itex]\frac {x+1}{2(\sqrt{2x+3}-2)} [/itex]

How did he come to this result??
Yes, you are correct.
 
  • #3
SammyS said:
Yes, you are correct.

Thank you no more discussion is needed. I'm going to assume Lang didn't intend for there to be "(" after the first two in the denominator
 
  • #4
r0bHadz said:
Thank you no more discussion is needed. I'm going to assume Lang didn't intend for there to be "(" after the first two in the denominator
... or he intended the denominator to be: ##\ 2(\sqrt{2x+3\,} -1)\,. ##
 
  • #5
SammyS said:
... or he intended the denominator to be: ##\ 2(\sqrt{2x+3\,} -1)\,. ##
True that.
 

What does it mean to "rationalize the numerator"?

Rationalizing the numerator refers to the process of rewriting a fraction so that the numerator (top number) does not contain any irrational numbers, such as square roots or cube roots.

Why is it important to rationalize the numerator?

Rationalizing the numerator is important because it helps us to simplify and compare fractions more easily. It also allows us to perform operations on fractions, such as addition and subtraction, more accurately.

How do you rationalize the numerator?

To rationalize the numerator, you can multiply both the numerator and denominator of the fraction by the same value. This value is usually the conjugate of the irrational number in the numerator, which is obtained by changing the sign of the irrational number.

What is the difference between rationalizing the numerator and denominator?

Rationalizing the numerator involves changing the numerator of a fraction, while rationalizing the denominator involves changing the denominator. The goal of both processes is to simplify fractions and make them easier to work with.

Can you give an example of rationalizing the numerator?

Sure! Let's say we have the fraction 3/√5. To rationalize the numerator, we would multiply both the numerator and denominator by the conjugate of √5, which is -√5. This would give us (-√5 * 3)/(-√5 * √5), which simplifies to -3√5/5.

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