Dimensions that maximize the area of the rectangle (KristaKingMath)

Learn how to calculate the derivative of a parametric curve and find the equation of the tangent line to the parametric curve at a given point t.

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Hi, I’m Krista! I make math courses to keep you from banging your head against the wall. ;)

Math class was always so frustrating for me. I’d go to a class, spend hours on homework, and three days later have an “Ah-ha!” moment about how the problems worked that could have slashed my homework time in half. I’d think, “WHY didn’t my teacher just tell me this in the first place?!”

[XPeachezNCreamX]

This is so useful and easy to understand, you went through all the steps so nicely!!! Thank you so much!!!!

[kristakingmath]

In this case, the area can't be minimized. See reply by @VeryEvilPettingZoo to @SuCKeRPunCH187 lower in the comments for a great explanation about why. :)

[LAnonHubbard]

I did find this video helpful. It's amazing how easy it is to forget things if you don't use them for a while so this helps me keep it fresh in my brain so that I will have it in my toolbox for when I do need it.

[cristyemru]

Thank you so much for clearly explaining each step! You're a life saver!

[kristakingmath]

I took the derivative of A=50x-x^2, which was the equation for the area of the rectangle after we solved for y and plugged in. I hope that helps! :)

[darsh]

Mate Ik it’s been like 8 years since this video came out but it literally saved my life today tq so much🙏🙏🙏

[johsmith]

Thank you so much for the help. Most of this was forgotten with time and you truly helped me relearn it all from scratch.

[lawrencedwarika]

You are very good at simplifying for easier understanding. I must say that to you.

[dusky]

I'm so confused, what did you do at 4:10?

[keriannee]

hey lady! u did my homework problem for me

[jaqandlu]

thankyou very much! I able to finish my task because of this!

[paramoregrl]

thank you! my professor put this question on our sample test I had no idea where to start!

[jordanmichael]

You're the best calculus girl on the internet. Your videos always have just what I'm looking for somehow.

[ryanbrown]

I know this was long ago but I have a test coming up and this helped so much. Thank you!!

[calculotv]

Excelente tú explicación.
Es buena idea aplicar el Criterio de la Segunda Derivada, para verificar que en x=25 hay un máximo, Saludos.

[xzaivierjames]

Do you happen to have the same video for the min area of the rectangle of 100?

[kristakingmath]

Yes, normally you should check that x=25 is a maximum, but in this case, the area can't be minimized, so you know that the critical point you found must be a maximum. :)

[biharibabu.]

Thank you mam for explaining in details 🙂

[CF-pbev]

Your videos are great. They have saved me from long frustrated nights studying

[kristakingmath]

Great explanation! Thanks for replying!! :D