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cassi999 · Oct 27, 2011, 04:56 PM

I don't know it keeps showing me these weird symbols its suppose to be

x^2=2yv-z
2yv=x^2+z
v=(x^2+z/2y
4.11

Unknown008 · Oct 27, 2011, 09:36 PM

1. Yes, the answer I got is 11.47.

2. No, I'm getting something totally different here... though you worked it out well.

$v = \frac{x^2 + z}{2y}$

$v = \frac{(2.5\times10^{-3})^2 + (1.2\times 10^{-6})}{2(3.5\times10^{-3})}$

cassi999 · Oct 30, 2011, 01:02 PM

That would give me 0.00017 as the answer... Is that right

Unknown008 · Oct 31, 2011, 12:11 AM

Hmm, I'm sorry, but this is not what I am getting, unfortunately.

$v = \frac{6.25\times 10^{-6} + 1.2 \times 10^{-6}}{7.0\times 10^{-3}}$

All right? A little easier like that?

$v = \frac{7.45\times 10^{-6}}{7.0\times 10^{-3}}$

cassi999 · Nov 1, 2011, 06:25 AM

okay 7.45/7.0 then you subtract the powers so it becomes 10^-3... which would give you 1.0642 *10^-3 =0.001064 is that right ?

Unknown008 · Nov 1, 2011, 06:57 AM

That's what I got :)

cassi999 · Nov 7, 2011, 10:13 AM

hi
can you check this for me
4ac^2=c^2+3ab when a=4.5 and b=3.6. make c the subject

4ac^2=c^2+3ab when a=4.5 and b=3.6
4*4.5*c^2 = c^2 + 3*4.5*3.6
18c^2 = c^2 + 48.6
17c^2=48.6
c^2 = 48.6/17

c = +/- sqr(48.6/17) = +/-1.6908

Unknown008 · Nov 7, 2011, 10:30 AM

Yea you can do it like that, but this defeats the purpose of making c the subject... :(

Start by moving c^2 on the left side, then factor c^2.

cassi999 · Nov 7, 2011, 10:35 AM

okay so
4ac^2 = c^2+3ab
4(4.5)c^2 = c^2 + 3(4.5)(3.6)
18c^2 = c^2 + 48.6
17c^2 = 48.6
c^2 = 48.6/17
c^2 = 2.86
c = 1.69

Unknown008 · Nov 7, 2011, 10:43 AM

No no no. You don't put in the numbers until you have c as the subject.

$4ac^2 = c^2 + 3ab$

$4ac^2 - c^2 = 3ab$

Forget the values of a and b for the time being and make c the subject of formula.

cassi999 · Nov 9, 2011, 05:50 AM

c^2=4ac^2+3ab is this arrangement right ?

Unknown008 · Nov 9, 2011, 06:04 AM

No, you have c^2 on both sides...

Take from the last line in my previous post. Factor out c^2 just like you would factor x here:

ax - 2x = x(a - 2)

cassi999 · Nov 9, 2011, 02:02 PM

hi
I tried it and this is what I got. :-)

4ac² - c² = 3ab

=> c²(4a - 1) = 3ab

=> c² = 3ab/(4a - 1)

c = √(3ab/(4a - 1))

cassi999 · Nov 9, 2011, 02:12 PM

4ac² - c² = 3ab

=> c^2(4a - 1) = 3ab

=> c^2 = 3ab/(4a - 1)

c = squr(3ab/(4a - 1))

cassi999 · Nov 9, 2011, 02:14 PM

sorry it suppose to be
4ac^2 - c^2 = 3ab
I don't know why it keeps showing these weird symbols

Unknown008 · Nov 9, 2011, 09:18 PM

Type them manually instead of copy/pasting from Microsoft word or something, but if I understood it well, you did a good job! Replacing the values of a and b in the last equation you got, that is:

$c = \sqrt{\frac{3a}{4a-1}}$

You should get c as 1.69 :)