# solve V1=(V2-u)/(1-uV2/C2) for V2

#### jhanson58

##### New member
I am trying to understand my math problem. I know what an exponent is. But what does it mean when X 2 you have a little 2 in the lower right hand corner.

V1=V2-u/1-uV2/C2 Solve for V2 How do I go about doing this.

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#### Klaas van Aarsen

##### MHB Seeker
Staff member
I am trying to understand my math problem. I know what an exponent is. But what does it mean when X 2 you have a little 2 in the lower right hand corner.

V1=V2-u/1-uV2/C2 Solve for V2 How do I go about doing this.
Welcome to MHB, jhanson58!

A little 2 in the lower right hand corner distinguishes variables.
So $x_1$ is a different variable from $x_2$.
We might also call them simply $x$ and $y$.

As for your equation, can you clarify it?
$$V_1=V_2-{u \over 1}-{uV_2 \over C_2}$$
But I suspect that is not what you intended.
What did you intend?

Btw, as you can see I moved your post to a new thread, since it's a new topic.

The problem is

V1=V2-u
-----
1-uV2
----
C2

Solve for V2

#### Evgeny.Makarov

##### Well-known member
MHB Math Scholar
Start by using parentheses. Every expression can be written in one line using parentheses. Remember the order of operations.

#### MarkFL

Staff member
The problem is

V1=V2-u
-----
1-uV2
----
C2

Solve for V2

On our toolbar, you will see a button with the $$\displaystyle \sum$$ character on it. Clicking this button will generate the MATH tags, between which you can put your $\LaTeX$ code. To see the code used by others, right click the expression, and from the pop-up menu choose Show Math As ► Tex Commands. You can then copy/past the code for your own use/modification.

There is a small learning curve to get familiar with the characters and commands, but once you get some practice it becomes second nature.

#### Klaas van Aarsen

##### MHB Seeker
Staff member
The problem is

V1=V2-u
-----
1-uV2
----
C2

Solve for V2

Is it like this?
$$V_1 = \frac {V_2 - u} {1 - \frac{uV_2}{C_2}}$$

Note that when you click Reply With Quote, you can see how I typed the formula and you can easily copy+paste it.

#### jhanson58

##### New member
I do not understand how to put the problem in correctly.when I right click on it. I do not see any symbols to help me.

#### Evgeny.Makarov

##### Well-known member
MHB Math Scholar
I do not understand how to put the problem in correctly. when I right click on it.
Well, you should right-click a mathematical expression (and then select "Show Math As ► Tex Commands") in another post, like the following expression from post #6:
$V_1 = \frac {V_2 - u} {1 - \frac{uV_2}{C_2}}$
You may need to turn Javascript on in your browser. If this does not work, use other suggestions above.

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#### topsquark

##### Well-known member
MHB Math Helper
It looks to be like a variant on the velocity addition formula from SR:
$$\large v_1 = \frac {v_2 - u} {1 - \frac{uv_2}{c^2}}$$

-Dan

#### Klaas van Aarsen

##### MHB Seeker
Staff member
It looks to be like a variant on the velocity addition formula from SR:
$$\large v_1 = \frac {v_2 - u} {1 - \frac{uv_2}{c^2}}$$

-Dan
Nice one!

Then, to solve $v_2$ from it, we can observe that in SR from the perspective of the other observer, the velocities are added instead of subtracted. Therefore:
$$v_2 = \frac {v_1 + u} {1 + \frac{uv_1}{c^2}}$$

#### Granny

##### New member
i need help! it says 0.999999.... is 1! how can That be?