View Full Version : Transpose formula questions and answers?
cassi999
Oct 13, 2011, 02:37 PM
transpose formula maths
transpose the formula to make z the subject and determine it value when w=4, x=1.5 and y=0.85
y=(2 x)(3-z)/4w
transpose the formula using z the subject and obtain its value when y=2*10^3 and x=750
y=3?(x^2 -z^2)
transpose the equations to make c the subject and determine its value when a=4.5 and b3.6
for a c^ =c^ 3 a b
b) transpose the equation to make v the subject and determine its value when a=0.75,u=3.6 and t=10.5
v^-u^/2a= u t 1/2 a t^
Unknown008
Oct 14, 2011, 01:33 AM
1. To make z the subject of formula,
a. multiply both sides by 4w
b. divide both side by (2+x)
c. subtract 3 from both sides
d. multiply both sides by -1.
Can you try that an post what you get? :)
cassi999
Oct 15, 2011, 02:25 PM
Really tired got random and weird answers.. could you try it.. and there was a mistake in the questions above .
a.) y=(2+x)(3-z)/4w
b.) y=3(x^2 -z^2)
Thank you
Unknown008
Oct 16, 2011, 06:52 AM
It's just as I said.
Here, let me show you, but promise me to try the others and post every line you come up with :)
y=\frac{(2+x)(3-z)}{4w}
1. To make z the subject of formula,
a. multiply both sides by 4w
4wy = \frac{(2+x)(3-z)}{\cancel{4w}}\times \cancel{4w}
4wy =(2+x)(3-z)
b. divide both side by (2+x)
\frac{4wy}{(2+x)} = \frac{\cancel{(2+x)}(3-z)}{\cancel{(2+x)}}
\frac{4wy}{(2+x)} =3-z
c. subtract 3 from both sides
\frac{4wy}{(2+x)} -3 =\cancel{3}-z \cancel{-3}
\frac{4wy}{(2+x)} -3=-z
d. multiply both sides by -1.
-1\times (\frac{4wy}{(2+x)} -3)=-1(-z)
-\frac{4wy}{(2+x)} +3=z
z = 3 -\frac{4wy}{(2+x)}
Now, if you understood why I did those, you would see that each step removed something that was 'attached' to z. Can you try out the others and post them here? Even the weird answers that you got, and how you got them, so that we know exactly what went wrong.
cassi999
Oct 16, 2011, 03:15 PM
okay.. I don't know how to convert steps into the formula with this equation... y=3(x^2 -z^2)
y=3(x 2 -z 2 )
(x 2 - z 2 ) = y/3
z =((x 2 - (y/3))
so that's (750^2 -z^2)-2*10^3/3
... 750^2-2000/3= 56183
I know something is wrong with the answer.. it looks funny
Unknown008
Oct 16, 2011, 11:04 PM
okay.. I don't know how to convert steps into the formula with this equation... y=3(x^2 -z^2)
y=3(x^2 -z^2)
(x 2 - z 2 ) = y/3
Good :)
z =((x 2 - (y/3))
No, you missed the square here, or you forgot to type it... but anyway, this should be:
z^2 = x^2 - \frac{y}{3}
z= \sqrt{\(x^2 - \frac{y}{3}\)}
so that's (750^2 -z^2)-2*10^3/3
I'm not sure why you did that... but if you want to make it 'not wrong', it should be equal to zero.
... 750^2-2000/3= 56183
I know something is wrong with the answer.. it looks funny
Can you try again with the new equation you got? :)
cassi999
Oct 18, 2011, 06:33 AM
okay so basically √(750^2-(2000/3)) = 749.5
Is that correct?
Thank you
Unknown008
Oct 18, 2011, 10:30 AM
Yes yes it is! :)
Okay, can you try the next one? Post what you came up with, just like the previous.
cassi999
Oct 22, 2011, 05:39 AM
hi I have done transpose could you check to see if it is correct
u=v-at where a=5 t=10 and u=25
2) s=1/2(v+u)t where s=1550 u=75 and t=6.1
3) h= v^/ 2g where h=2.5*10^6 and g=9.81
are the questions
answers
u = v - at
v = u + at
= 25 + 50 = 75
s = 1/2(v + u)t
2s/t = v + u
v = ((2s)/t) - u
= (3100/6.1) - 75
h = v^2/2g
v^2 = 2hg
v = sqrt(2hg)
= sqrt(2 * 2.5 * 10^6 *9.81)
I didn't understand this one though
4) x=¹(2yv-z) where x=2.5*10-^3 and z=1.2*10-^6
Unknown008
Oct 22, 2011, 07:04 AM
Good! Very good even! :)
And... the last one didn't come out well... there's a weird symbol in there :(
cassi999
Oct 23, 2011, 03:52 PM
Can u go through with the last question Thank you
Unknown008
Oct 24, 2011, 12:08 AM
I would be glad to, but as I told you there is this "¹" symbol which I don't know what that means...
cassi999
Oct 25, 2011, 01:20 PM
Hi
I can't see that weird a symbol do u mind showing ot to me please
Thanks
Unknown008
Oct 26, 2011, 02:55 AM
Can you see that?
http://p1cture.it/images/68bbf1f8c7df29e1b2e9.png
cassi999
Oct 26, 2011, 01:33 PM
u^2+ v^2-u^2=2a(ut+1/2 at^2)+u^2
I can not use the cancel out sign.. n could not copy n paste it from word.. but when u^2 is added in both sides you basically cancels out u^2 from each side... the when you said square root it.. do you then make v2 as the subject? For e.g. v^2 = √-u^2=2a √(ut+1/2 at^2) is that right
Thank you
Unknown008
Oct 27, 2011, 08:15 AM
Okay, now I'm confused at what you're asking for.
For this:
v^2 - u^2 = 2a\(ut+\frac12 at^2\)
You did well with adding u^2, though it would be better to put in on the right of the terms, like this:
v^2 - u^2 +u^2= 2a\(ut+\frac12 at^2\) +u^2
It doesn't change anything, but it helps you to see what is there a little better, I think.
This now gives:
v^2 = 2a\(ut+\frac12 at^2\) +u^2
Take the square root on both sides, right.
\sqrt{v^2} = \sqrt{2a\(ut+\frac12 at^2\) +u^2}
v = \sqrt{2a\(ut+\frac12 at^2\) +u^2}
cassi999
Oct 27, 2011, 10:33 AM
hi
its x=√(2yv-z) where x=2.5 *10^-3 y=35-10^-3 and z=1.2-10^-6.
for this question v^-u^/2a= u t 1/2 a t^
i have added u^2 for both sides but i didn't know what to do to v^2 to make it the subject it was confusing i got 57.22 is it correct or have i done it wrong thanks
Unknown008
Oct 27, 2011, 10:48 AM
I'm getting something else. Did you see my above post when it came to v?
v = \sqrt{(2(0.75)((3.6)(10.5) + (0.5)(0.75)(10.5^2))+3.6^2}
This does not get me 57.22...
Okay, I give up on trying to understand the symbol the other one. But I guess it's some square root?
x = \sqrt{2vy - z}
Start by squaring both sides.
cassi999
Oct 27, 2011, 02:53 PM
Yes it's a square root sign I don't know why it keeps doing that.
I have squared rooted it and got 11.47
cassi999
Oct 27, 2011, 04:49 PM
hi
X² = 2YV – Z
2YV = X² + Z
V = (X² + Z) / 2Y
is the answer 4.11
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 :)