Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Comments on What to do when there's lot of function of time? (For integration) Should I consider them as constant?

Post

What to do when there's lot of function of time? (For integration) Should I consider them as constant?

+0
−1

Let I have a function which is looking like this

$$f=\int\frac{l \ \mathrm {dt}}{\dot{\theta}r\dot{r}}$$

Here $\dot{\theta}$, $r$, $\dot{r}$ and $l$ all of them are function of $t$. For differentiating respect to time I simply increase "dot". But what to do for integration? Should I consider them as constant?

What will happen if I forcefully say that $r$ isn't constant? $r$ is changing every single sec.

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

1 comment thread

It is not true that for differentiating you simply “increase dot”. Rather, you apply the differentiat... (1 comment)
It is not true that for differentiating you simply “increase dot”. Rather, you apply the differentiat...
celtschk‭ wrote about 3 years ago

It is not true that for differentiating you simply “increase dot”. Rather, you apply the differentiation rules. Having said that, while taking the derivative usually can be done quite mechanically, integration cannot be done that way (well, technically it can, but the algorithm is so complicated that even computer algebra systems often don't fully implement it). Indeed, many integrals cannot be solved analytically at all.