Integration sum

[ancient edge]

What is the exercise?

[visual oracle]

I have to intergrate the formula seen at the first line of the paper

[ancient edge]

You should write that in your solution

Also use equality in your solution, with an explanation of your step

Do you use ( ) as a notation for integration?

If you want to integrate a product, you can't just take the product of both integrations.

You could try to use integration by parts, or try to substitute something

[visual oracle]

The solution is wrong, i know but i want to know why its wrong

I know the answer already because i got the answerbook

[ancient edge]

You should first do something about your notation. Why is it that your solution of an integration doesn't contain an integration symbol or dx?

$\int f(x) \cdot g(x) \dd x \neq \int f(x) \dd x \cdot \int g(x) \dd x$

[rose wadi]

WanderingLethe

[ancient edge]

And that does not hold

[ancient edge]

Vot?

[versed hamlet]

1 cos

[visual oracle]

[ ] is intergration

i splitted the parts

i thought i could split all parts up and use [ ] for the things i intergrated

Thats how i learned it at scchool

[ancient edge]

Middelbare? The aren't that many elementary rule for integration as there are for differentiation. It isn't as easy as following an algorithm, as with differentiation, you need to try things out.

That notation is really weird, also didn't you have to use the equal sign =?

For this problem you can substitute u = sin x, such that dx = du / cos x, and therefore

$\int \frac{\cos x}{\sin^2 x} \dd x = \int \frac{1}{u^2} \dd u$

[rose wadi]

WanderingLethe