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 How to determine area of square using Calculus in Cartesian coodinate?

Post

How to determine area of square using Calculus in Cartesian coodinate?

+1
−2

I was studying determination of area in Calculus. So, I decided to calculate area of rectangle using Calculus.


Let, length of a line of a square is $5$. So, I decided to make an equation for that. I took $x^2+y^2=\sqrt{25}$. Firstly, it was looking perfect to me. Then, when I was calculating for $y=1$ then, I noticed I got $x=4,6$ (where 6 is wrong).

coordinate

I drew the above picture (Sorry! I don't have proper "picture" maker in system)..

We know $$\int_{-5}^{5}y\mathrm dx$$ $$=\int_{-5}^{5} \sqrt{\sqrt{25}-x^2}\mathrm dx$$

If I integrate it than, I get imaginary number and infinite number. So, I think I took the wrong equation. How would you determine area of square using Integration (when length of a line is $5$)?

Note : Use Cartesian Coordinate.

Ohh! Sorry. I wrote $x^2+y^2=\sqrt{25}$ but, when doing that in notepad I was doing using $x+y=\sqrt{25}$ then, I got $50$...

$$\int_{-5}^{5} \sqrt{25}-x \mathrm dx$$ $$[\sqrt{25}x]-\frac{x^2}{2}]_{-5}^5$$ $$\sqrt{25}(5)-\sqrt{25}(-5)-\frac{25}{2}+\frac{25}{2}$$ $$2\sqrt{25}(5)$$ $$50,-50$$

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

1 comment thread

$x^2+y^2=5$ is the equation of a circle (of radius $\sqrt5$) (2 comments)
$x^2+y^2=5$ is the equation of a circle (of radius $\sqrt5$)
Moshi‭ wrote over 2 years ago

$x^2+y^2=5$ is the equation of a circle (of radius $\sqrt5$)

deleted user wrote over 2 years ago

Moshi‭ Yeah! It was my mistake.