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# C2: Application of Differentiation Again watch

1. Q: This diagram represents a rectangular sheet of metal 8 cm by 5 cm. Equal squares of side x cm are removed from each corner, and the edges are then turned up to make an open box of volume v cm^3. Show that v = 40x - 26x^2 + 4x^3
Hence find the maximum possible volume, and the corresponding value of x.

Help would really be appreciated
2. (Original post by TarotOfMagic)
huh?
3. (Original post by TarotOfMagic)

Q: This diagram represents a rectangular sheet of metal 8 cm by 5 cm. Equal squares of side x cm are removed from each corner, and the edges are then turned up to make an open box of volume v cm^3. Show that v = 40x - 26x^2 + 4x^3
Hence find the maximum possible volume, and the corresponding value of x.

Help would really be appreciated
For the first bit, can you see that the lengths of the sides will now be 8-2x and 5-2x? Then the height will be x. Multiplying these together will give you the volume
4. (Original post by TarotOfMagic)

Q: This diagram represents a rectangular sheet of metal 8 cm by 5 cm. Equal squares of side x cm are removed from each corner, and the edges are then turned up to make an open box of volume v cm^3. Show that v = 40x - 26x^2 + 4x^3
Hence find the maximum possible volume, and the corresponding value of x.

Help would really be appreciated
wow what a question

did you try draw the net? is it possible for you to post an attempt?

Edit: too slow
5. (Original post by DylanJ42)
huh?
Sorry, I accidently submitted it without writing the question: I have edited it now.
6. (Original post by TarotOfMagic)
Sorry, I accidently submitted it without writing the question: I have edited it now.
how are you getting on with it?
7. (Original post by tinkerbella~)
For the first bit, can you see that the lengths of the sides will now be 8-2x and 5-2x? Then the height will be x. Multiplying these together will give you the volume
Thanks so much! I have solved the question correctly.
8. (Original post by TarotOfMagic)
Thanks so much! I have solved the question correctly.
Awesome! No problem
9. (Original post by tinkerbella~)
Awesome! No problem
Are you the maths fairy
10. (Original post by Zacken)
Are you the maths fairy
No that's you dear
11. (Original post by tinkerbella~)
No that's you dear
I am the maths fairy
12. (Original post by Zacken)
I am the maths fairy
If I leave math questions under my pillow, do I get money?

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13. (Original post by drandy76)
If I leave math questions under my pillow, do I get money?

Posted from TSR Mobile
You get £ for every maths problem.
14. (Original post by Zacken)
You get £ for every maths problem.
How does one get negative money ?
15. (Original post by zetamcfc)
How does one get negative money ?
I'd be stealing it from him, that was the point. Vector quantity and all.
16. (Original post by zetamcfc)
How does one get negative money ?
well you could go to a £9000 a year uni to learn maths for a start

Edit: missed the joke too
17. (Original post by Zacken)
I'd be stealing it from him, that was the point. Vector quantity and all.
I see... getting quite late... brain not working well...
18. (Original post by drandy76)
If I leave math questions under my pillow, do I get money?

Posted from TSR Mobile
if you leave money under your pillow you get a maths problem
19. (Original post by Zacken)
I'd be stealing it from him, that was the point. Vector quantity and all.
My money is kept in 5 dimensional space, your 3rd dimensional translations have no chance

Posted from TSR Mobile
20. (Original post by DylanJ42)
well you could go to a £9000 a year uni to learn maths for a start
I have.......

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