02/20/2018, 09:55 PM
Okay, let us sign i[x] to just i and I[x] to just I where I[x] = int i[x] dx.
D := d/dx
So
D I = i
D i = i'
D i I = i' I + i^2 = i' I - 1
D I i = i^2 + I i' = I i' - 1
Therefore
i' I = 1 + (i I)'
and
I i' = 1 + (I i)'
D 1 I = D I 1 = 0 + i = i
But
D i÷I = (i' I - i^2)÷I^2 = (i' I + 1)÷I^2 = (2 + (i I)')÷I^2
D I÷i = (i^2 - I i')÷i^2 = I i' = 1 + (I i)'
D I÷i = -D i I = 1 - i' I
Thus
D I i = - i' I = I i' - 1
furthermore
i' I = 1 - I i'
I do not have to talk about i' I is not I i', right?
D 1÷I = (0 - i)÷I^2 = - i÷I^2
What is next?
The only useful information is that 1 ÷ i = -i ... or anything else?
D := d/dx
So
D I = i
D i = i'
D i I = i' I + i^2 = i' I - 1
D I i = i^2 + I i' = I i' - 1
Therefore
i' I = 1 + (i I)'
and
I i' = 1 + (I i)'
D 1 I = D I 1 = 0 + i = i
But
D i÷I = (i' I - i^2)÷I^2 = (i' I + 1)÷I^2 = (2 + (i I)')÷I^2
D I÷i = (i^2 - I i')÷i^2 = I i' = 1 + (I i)'
D I÷i = -D i I = 1 - i' I
Thus
D I i = - i' I = I i' - 1
furthermore
i' I = 1 - I i'
I do not have to talk about i' I is not I i', right?
D 1÷I = (0 - i)÷I^2 = - i÷I^2
What is next?
The only useful information is that 1 ÷ i = -i ... or anything else?
Xorter Unizo

