Which of the following expressions are polynomials in one variable and which are not ? Give reasons for you answer.
(i) `3x ^(2) - 2x + 5`
(ii) `x ^(2) + sqrt2`
(iii) `p^(2) - 3p +q`
(iv)`y + (2)/(y) (y ne 0)`
(v) `5 sqrtx + x sqrt5`
(vi) `x ^(100) + y ^(100)`