f'(x)
When a function always spits out 11, no matter what you throw at it. It's like the math version of a stubborn kid who only wants 11.
My math teacher said this function is the worst. I said, 'It's not the worst. It just wants 11.'
That function is so annoying, it only gives you 11, no matter what.
The function is like a kid who only likes 11 and won't take no for an answer.