1. did you mean
4/(3 + √5)
or
4/3 + √5 , the way you wrote it.
secondly, what do you want to "solve" ?
are you studying rationalizing the denominator?
My question also applies to the other two questions
Posted by NEED HELP on Monday, September 29, 2014 at 9:12pm.
Have three problems and I'm really confused how to solve/simplify
1. 4/3+square root of 5
2. -4/-4+4square root of 2
3. 1/1+ square root of 2
2 answers
recall that (a+b)(a-b) = a^2-b^2
so, (3+√5)(3-√5) = 9-5 = 4
So, to simplify such fractions, look for the "square conjugate" if you will, of the denominator.
4/(3+√5) = 4(3-√5) / (3+√5)(3-√5)
= 4(3-√5)/4 = 3-√5
And do the others the same way. You can check your answers at wolframalpha.com
For the first one, just enter
4/(3+√5)
in the box and it will show various data about the expression
http://www.wolframalpha.com/input/?i=4%2F%283%2B%E2%88%9A5%29
so, (3+√5)(3-√5) = 9-5 = 4
So, to simplify such fractions, look for the "square conjugate" if you will, of the denominator.
4/(3+√5) = 4(3-√5) / (3+√5)(3-√5)
= 4(3-√5)/4 = 3-√5
And do the others the same way. You can check your answers at wolframalpha.com
For the first one, just enter
4/(3+√5)
in the box and it will show various data about the expression
http://www.wolframalpha.com/input/?i=4%2F%283%2B%E2%88%9A5%29
1 answer