What exactly do you mean? I think your notation is a bit messed up. Here's a standard definite integral. You can double-click to see the code required:
Sorry, I was figuring out how to type integral symbol here... The upper limit of the integral is x, which is not displayed on the screen
To make it clear, the lower limit of the integral is a, the upper limit of the integral is x and the variable of integration is t. Thanks.
No, there are no x's. When you compute an antiderivative, you completely ignore the limits (in this case, a and x) of the integral. The antiderivative depends entirely on the integrand (in this case, t), and the variable of integration (also t). Try again: what do you get?