T-Shirt With An Attitude

So what's all this about? It's a pickup line using calculus. Try to solve the equation & you will come up with a rude pickup line.
Though to the 99% of the people who will see this, it wont make any sense as what is the result of evaluation of this math expression, & apart from this a further 0.4% (plus or minus a bit) are more likely to jump on the erroneous conclusion that the integral evaluates to 42 without trying to plug in the values.
Still confused? So here is how it works:

2xdx integrates as x squared; to evaluate the integral of 2xdx over the interval from 10 to 13, you subtract the value at the bottom of the interval from the value at the top of the interval.
At the bottom of the interval, setting x equal to 10 yields 100, because 10 x 10 = 100. At the top of the interval, set x equal to 13, calculate x squared (13 x 13), and then subtract 100 from it. At this point, it is essential to note the presence of the question mark.
That's what makes this a rude pickup line.
If this still doesn't make sense, it may be helpful to note that the numeric result of the calculation is, in the idiomatic slang of most of the population of the United States, suggestive of a particular interpersonal activity which does not fall under the heading of things permitted in public.

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