Question

If a=2+root over 3 then find the value of a-1/a

Answer 1

a=2+√3

then, 1/a=1/2+√3=1/2+√3*2-√3/2-√3=2-√3/4-31/a=2-√3

now

a-1/a=2+√3-(2-√3)a-1/a=2+√3-2+√3a-1/a=2√3

this is your answer