Question

1.If a=6+2√3, find the value of
a- (1/a).
2. if x=7+√40, find the value of
x+(1/x).

Answer 1

a_1/a

6 +2×(3)^1/2 +1/6+2(3)^1/2 = (6+2(3)1/2)^2 _1/6+2(3)1/2= 36 + 2×6×2×(3)1/2 + 6 _1 /6+ 2(3)1/2 =36+24(3)1/2 +5 /6+2(3)1/2