In Raabe’s test, for a positive term series ∑ un, \(\mathop {\lim }\limits_{n \to \infty } n\left( {\frac{{{u_n}}}{{{u_{n + 1}}}} - 1} \right) = k,\) then which of the following statements are false?
1
The series diverges for k < 0
2
The series converges for k > 1
3
This test gives satisfactory results for k = 1
4
This test is usually used when ratio test fails