Question

Dividing Radicals

I used this for the redial sign \/

Problem:

30 \/15
_______

4 \/10

The book says the answer is 15/4 \/6 (15/4 with radicand of 6). I have tried to solve the problem several different ways. I do not arrive at this answer.

Answer 1

how about this :
30√15 / (4√10)
= 15√3 / 2√5 now multiply top and bottom by √2
= 15√6 /4

Answer 2

Thank you for your response.

I did get 15\/3 and 2\/5. Why would you then mutiply by \/2?

The answer in the book is 15/4 with radicand of 4 not a radicand of 6. Are you also showing that there is a missprint in the book and the racdicand is 4?
I have several missprints int he book.

Answer 3

At the top of your post you said the book answer was 15/4 with radicand of 6
and now you say it is 15/4 with radicand of 4 not a radicand of 6. ???


It is generally considered "poor form" to have a radical in the denominator
This goes back to pre-calculator times.
What would you rather have done back in 1950:
divide by √2 which would be dividing by 1.4142136...
or divide by 4 ?

Answer 4

BTW, I just noticed that my second last line in my solution is
15√3 / 2√5

that should have been
15√3 / 2√<b>2</b>

Answer 5

If is 4 \/10. Why would it be 2 \/2 and not the 2 \/5?

Answer 6

OK, from the start:

30√15 / (4√10) divide top and bottom by 2√5
= 15√3 / 2√2 multiply top and bottom by √2
= 15√6 /4