Question

I don't know whether he is there or not

Answer 1

Answer:

Whether

Explanation:

Why do you need the negative in the second clauses in your first two sentences, ebay? In the third, it should be "Whether he comes or not", I think.We don't use "whether" with negative statements.

I don't know whether it will rain tomorrow.

I don't know if it will rain tomorrow.

I don't know if it will not rain tomorrow. (It's been raining every day for three weeks, and I don't know if tomorrow will be any different