Math olympiad | Algebra | Simplify the surd expression | โˆš(๐Ÿ–+โˆš๐Ÿ”๐Ÿ‘) โˆ’โˆš(๐Ÿ–โˆ’โˆš๐Ÿ”๐Ÿ‘) | Can you solve ?

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Math olympiad | Algebra | Simplify the surd expression | โˆš(๐Ÿ–+โˆš๐Ÿ”๐Ÿ‘) โˆ’โˆš(๐Ÿ–โˆ’โˆš๐Ÿ”๐Ÿ‘) | Can you solve ?

This video discusses a famous problem on algebra taken from an olympiad. Surd Simplification problem

#mathematics
#maths
#mathsolympiadpreparation
#mathsolympiad
#mathematicsolympiad
#mathsquestion
#surds
#surds_and_indices
#simplification
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Rather than square the whole expression and then run into the problem of whether to take a negative as well as a positive square root, you could simplify the two expressions under the outer square roots by using the identities
(a + b)^2 = a^2 + b^2 + 2ab and (a-b)^2 = a^2 + b^2 - 2ab.

sqrt (8 + sqrt63) - sqrt(8 - sqrt63)
= [sqrt (16 + 2 sqrt63)]/sqrt2 - [sqrt (16 - 2sqrt63)]/sqrt2
multiplied by 2 inside the sqrt sign; divided by sqrt2 outside
= [sqrt (9 + 7 +2 sqrt9.sqrt7)] /sqrt2 - [sqrt (9 + 7 - 2 sqrt9.sqrt7)]/sqrt2
= [sqrt (sqrt9 + sqrt7)^2]/sqrt2 - [sqrt (sqrt9 - sqrt7)^2]/sqrt2
= [sqrt9 + sqrt7]/sqrt2 - [sqrt9 - sqrt7]/sqrt2 Outer square root cancelled by square
= [sqrt9 + sqrt7 - sqrt9 + sqrt7]/sqrt2
= 2sqrt7/sqrt2 2/sqrt2 = sqrt2
= sqrt2.sqrt7
= sqrt14

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