Who Am I ?
I am your constant companion. I am your greatest helper, or your heaviest burden. I will push you onward, or drag you down to failure. I am at your command. Half of the task you do, you may just as well turn over to me. I will do them quickly and correctly.
I am easily managed, but you must be firm with me. Show me exactly how you want something done. After a few lessons I will do it automatically. I am the servant of all great people; of all great failures as well. Those who are great, I have made great. Those who are failures, I have made failures.
I am not a machine, though I work with all the precision of a machine, plus the intelligence of a person. You may run me for profit, or run me for ruin--it makes no difference to me.
Take me -- train me -- be firm with me, and I will place the world at your feet. Be easy with me, and I will destroy you!
And what can this possibly have to do with calculus?