Simple primitive question (1 Viewer)

[nahi11]

Hi,

Can someone please help with this question.

Find the primitive of:


When I do it i get x^2 / 2 + C. However, the answers a bit different.

Thanks

 

[AAEldar]

 

[nightweaver066]

Hi,

Can someone please help with this question.

Find the primitive of:
View attachment 24428

When I do it i get x^2 / 2 + C. However, the answers a bit different.

Thanks

It's not entirely all that simple. You have to know log integration to do it.

 

[D94]

Split the function into two parts then find the primitive:



EDIT: oh damn, too slow.

 

[nahi11]

Thanks for the reply's.

Lol where did the post by the greatest99.9 go? That was the answer lol.

The answer says X^2/2 + x + C

I don't think they expect us to use logs yet.

Perhaps you guys can see a fault in my reasoning.

I understand up to f'(x) = x + x^-1 .
So then when I integrate I raise the power by 1 right and divide by that power?

So therefore,

X^2 /2 + x^-1+1
X^2/2 +x^0? (-1+1=0?_
X^2/2 + 1 + C

EDIT: rep+ to all of you for your help.

 

[D94]

Thanks for the reply's.

Lol where did the post by the greatestsimpson go? That was the answer lol.

The answer says X^2/2 + x + C

I don't think they expect us to use logs yet.

Perhaps you guys can see a fault in my reasoning.

I understand up to f'(x) = x + x^-1 .
So then when I integrate I raise the power by 1 right and divide by that power?

So therefore,

X^2 /2 + x^-1+1
X^2/2 +x^0? (-1+1=0?_
X^2/2 + 1 + C

No, because when you divide by that power, you are dividing by 0 (zero), but you can't do that. The answer is wrong or the question is wrong.

 

[nahi11]

Thanks for that.

However, I wonder how TheGreatest99.95 got the answer? He soon deleted the post afterwards though.

 

[nahi11]

Ok anyway I figured out that this wasn't supposed to included in the schools past paper. Wasted a solid 30 mins over that lol.To solve it you need use logs as shown above.

Again thanks for the help.

 

[TheGreatest99.95]

I didnt realise i couldnt do that kinda question, so i deleted it. sorry
I havent learnt log integration yet