It depends on how many dollars you are talking about since your first obstacle is overcoming the trading fees of buying and selling..
Billions of dollars and euros are traded every day by professional traders and they are making profits on very tiny changes in the exchange rates. Over the long-term, monthly or even years, if you can correctly guess the exchange rate movements you might squeeze out a small profit but you aren't going to make much. The euro and dollar don't move that much because the economies behind them are extremely large and they are major trading partners, too. A ten percent movement in a year would be enormous. The chances you'd lose your shirt are very high because the people on the other side of your trades are doing this for a living and have highly-developed computer programs doing massive trades in a fraction of a second. By the time you blink, they will have been in and out of the trade you are planning to make several times. THere are better ways to make money.
In 2011, the EUR/USD changed from 1.36 to 1.27, or about nine cents.
In 2012, the change was from 1.27 to about 1.31, or about four cents.
In 2013, the change was from 1.31 to about 1.36, or about five cents.
Unless you are talking about investing millions of dollars, it probably wouldn't be worth tying up your money for that long and paying the exchange fees.
is it possible where i can take my us dollars and buy euros with them then when the exchange rate gets really high is can trade them back to get profit?
