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Can't figure out the answer. Help pls?

Hi everyone. Can someone pls help me with this maths question pls?

2 / √ 2 + √ 8

Apparently the answer is

3√2

I don't see how you can get that answer :frown:

^{Thanks in advance!!}

Reply 1

username1162972

Original post by bibliobuli

Hi everyone. Can someone pls help me with this maths question pls?

2 / √ 2 + √ 8

Apparently the answer is

3√2

I don't see how you can get that answer :frown:

^{Thanks in advance!!}

Do you know how to rationalise it?
I assume it is (2/sqrt(2))+sqrt8
So note 8=4x2
And try getting rid of the sqrt2 at the bottom of 2/root(2)

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Reply 2

markovchain17

rt8 = 2rt2

means 2/(rt2+2rt2) which is 2/3rt2 then u rationalise so 2rt2/6 which is rt2/3

Posted from TSR Mobile

(edited 8 years ago)

Reply 3

markovchain17

Unless u meant 2/rt2 + rt8 amd not 2/(rt2 + rt8) then it's just 2/rt2 + 2rt2 so rationalise 2/rt2 which is 2rt2/2 which is rt2, then add 2rt2 which is 3rt2

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Reply 4

Rather_Cynical

Mathematical notation using text is pretty hard to understand, apologies. This is the step by step to get your answer:

2 = sqrt(2) x sqrt(2).
2/sqrt(2) = sqrt(2) x sqrt(2)/sqrt(2) = sqrt(2)
sqrt(8) = sqrt(2) x sqrt(4)
sqrt(8) = sqrt(2) x 2

Therefore 2/sqrt(2) + sqrt(8) = sqrt(2) + 2(sqrt(2)) = 3(sqrt(2))