Cogent reasoning is different from deductive reasoning because the premises and conclusions of cogent arguments are determined to be most likely true and to lead to conclusions that are probably true. A cogent argument is one for which there is good evidence for the premises and conclusion, and thus is considered plausible or likely.
For your initial post: 

Create a cogent argument.
Explain why you think the premises are likely to be true. Explain why the conclusion is likely true as well.
Show how the conclusion can still be false even if your premises are true.