If a = (3^1/2 + 2^1/2)^-3 and b = ((3^1/2 - 2^1/2)^-3 then the value of (a+1)^-1 + ( b+1)^-1 is
a)48 root 2
b)50 root 3
Not sure if there's an easier way to do this, but if then multiplying it out yields
For ease let's use notation and , so that:
This gets a little messy, but it boils down to:
To finish you just need to sub in the values for x and y and see what you get.