Question

Can someone help me find the value of r in this equation: 2 x pi x r(.5) + 4pi r^2= pi

Answer 1

Is this what you equation looks like?
\(2\pi r(.5) + 4\pi r^2 = \pi\)

Answer 2

yess

Answer 3

OK. In the first term, the constants can be combined.

Answer 4

Do you know how to do that?

Answer 5

it would be πr+ 4πr^2 right?

Answer 6

sorry i'm new to this so i'm not sure how to add the pi sign and such

Answer 7

You can use the equation editor or learn \(\LaTeX\). The minimal amount of \(\LaTeX\) needed here is easy to learn.

What is \(2 \times 0.5\)?

Answer 8

Nevermind, I'm an idiot and you are correct.

Answer 9

So you have \(\pi + 4\pi r^2=\pi\) correct?

Answer 10

pi r

Answer 11

http://openstudy.com/study#/groups/LaTeX%20Practicing!%20%3A)
For help learning \(\LaTeX\) if you so desire.

Answer 12

alright thanks

Answer 13

If you divide the entire equation by \(\pi\), what do you get?

Answer 14

r+4r^2=1

Answer 15

At this point, I would move everything to the left side and factor (or use the quadratic formula).

Answer 16

Unless I've made a stupid mistake, this answer is going to have a radical in it.

Answer 17

uh oh, this is part of a larger question and r means radius... but the work makes sense so thanks for your help!

Answer 18

OK. Feel free to ask another question if you can't work it out. :-)

Answer 19

do you mind if i explain the bigger question? maybe i set this up wrong

Answer 20

Sounds like a good idea.

Answer 21

overview: we're working with a vitamin c tablet thats the shape of a right circular cyinder w a hemisphere attached at each end

Answer 22

one brand of tablets has a total length of 2 cm and a diameter of .5 cm. i found the surface area for it, which i think is \[\pi\]

Answer 23

now i have a tablet in which the cylinder has an altitude of .5 cm. find the diameter of the hemispheres of the new tablet if the surface area is the same as the first one

Answer 24

By total length, do you mean height? And what do you mean by altitude?
If you could draw a picture using the draw button below, it may make more sense to me.

Answer 25

i found all that confusing too. total length of the cylinder and hemispheres. altitude means height of the cylinder i think