Adding and Subtracting RadicalsDate: 03/08/2001 at 22:08:38 From: Mike Edmondsom Subject: Adding and subtracting radicals Simplify: (4 Rad 6) + (2 Rad 7) + (1 Rad 24) - (1 Rad 28) Date: 03/09/2001 at 08:27:44 From: Doctor Wolfson Subject: Re: Adding and subtracting radicals Hi Mike, While you can't directly add radicals with different radicands (numbers under the radical), you can sometimes simplify the radicand so that it can be combined with another. For instance, if I asked you to simplify: (5 Rad 5) + (2 Rad 20) 20 is the same as 4 * 5, so the second term of the problem can be rewritten: (2 Rad (5 * 4)) There is a rule for radicals that Rad (a * b) = (Rad a) * (Rad b) so I can again rewrite that term as: (2 * (Rad 5) * (Rad 4)) Rad 4 = 2, so this becomes: 2 * Rad 5 * 2 = 4 * Rad 5. Finally, I can combine this term with the original first term, because both are multiples of Rad 5: (5 Rad 5) + (4 Rad 5) = (9 Rad 5) The original problem you asked is very similar, and you can use this method to reduce it. I hope this helps. Feel free to write back if you'd like further clarification. - Doctor Wolfson, The Math Forum http://mathforum.org/dr.math/ |
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