Both ways are need for some basic capital and investitions. To trade you need big sum of money to feel the profit and for mining you have to buy necessary equipment, which is not so cheap, so, you have to look at all pluses and minuses of both mathods to decide what is better to you.
If you are only starting to trade then it's fine to invest smaller amount of money. You can simply buy a portion of bitcoin and use it somewhere or any exchange that you will be satisfied on using it. But in mining, it's the big deal there, you must invest big amount for the mining rig you need in able to earn bigger.
Trading requires knowledge and there is no point jumping into the trading without any knowledge and experience. That way we will only lose the coins. Better to study first and then start trading. Keeping the bitcoin only and doing nothing is a sign of laziness.
On the contrary, I believed that it is much better to trade with little or at least basic knowledge only. And try to learn as you go a long. Because when you try to learn everything, you will probably missed a lot of opportunity to earn. And learning is never ending. When are you going to stop learning trading? So much better to invest only a certain amount that you are comfortable to loss and see how it pans out for you.