- #51

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You had to subtract the k=0 term, which ended up being just "x".

I don't see it back in your integrated result.

Let me explain with an example.

Suppose you have the function f(x)=x^{2}+ 3

Now you know that f(0)=3 don't you?

Taking the derivative we get f'(x)=2x.

Taking the integral again we get [itex]\int f'(x)dx = x^{2}+ C[/itex]

(This is called an indefinite integral, since the boundaries were not given.)

As you can see the result is not equal to the original function - we lost the '3' in the process.

But since we know that f(0)=3, we can deduce that the integration constant C must be 3.

In which step should i substitute zero to get the constant?