Angela780
vivek123
Guys,
There is simple method.
[ 1/(sqrt3-sqrt2)]^2
= [(sqrt3+sqrt2)/(3-2)]^2
= (sqrt3+sqrt2)^2
= 3+2+2*sqrt3*sqrt2
= 5+2*sqrt(6)
Vivek, can you explain this to me?
Sure,
[ 1/(sqrt3-sqrt2)]^2 ----------------- (1)
The denominator is (sqrt3-sqrt2), in such problems, if we can get the denominator in simpler form, great!
Multiply & divide (1) by (sqrt3 + sqrt2)
= [
(sqrt3 + sqrt2)/
((sqrt3 + sqrt2)(sqrt3 - sqrt2))]^2 ------------------------------- (2)
Notice that, now the denominator is in the form, (a-b)(a+b)
we know that, (a-b)(a+b) = a^2-b^2
i.e. (sqrt3 + sqrt2)(sqrt3 - sqrt2) = (sqrt3)^2 - (sqrt2)^2 = 3 - 2 = 1
Put this value in equation (2)
= [(sqrt3+sqrt2)/1]^2
= (sqrt3+sqrt2)^2
Now apply (a+b)^2 = a^2+b^2+2ab
= 3+2+(2*sqrt3*sqrt2)
= 5+2*sqrt6