# B Algebra issue

1. Mar 31, 2016

### Einstein's Cat

Say if
C = square root (a^2 + b^2),
How could one make the term "b" the subject of the equation? Thank you for your help.

2. Mar 31, 2016

### ProfuselyQuarky

What's the opposite of a square root?

3. Mar 31, 2016

### Ssnow

you can start doing the square of your equation (both side), so $C^{2}=a^{2}+b^{2}$.

4. Mar 31, 2016

### ProfuselyQuarky

The OP was supposed to answer

5. Mar 31, 2016

### Ssnow

Only an input ... , now it is your turn ...

6. Mar 31, 2016

### ProfuselyQuarky

$C^2=a^2+b^2$
$b^2=C^2-a^2$

Now, @Einstein's Cat what's the last step?

7. Mar 31, 2016

### symbolipoint

Let me play dim-witted for a few seconds:
There is a variable and an expression and these are related by equality. How would any of that be or have a "subject"?

Now let me play as if I know what is really wanted:
Just use INVERSE operations to undo what has been done to b, so you solve the equation for b, to have a formula to show what is an expression for b.

8. Mar 31, 2016

### ProfuselyQuarky

Aw, you knew what he/she meant

9. Mar 31, 2016

### Einstein's Cat

Jesus! I just realised how stupid my question was; numerous apologies for diminishing your lives

10. Mar 31, 2016

### ProfuselyQuarky

No prob! It was amusing.

11. Mar 31, 2016

### symbolipoint

Maybe I should not have said the way I did say.
The way "subject" is used seems to expect that the equation is a sentence and works according to the grammar of the language, but such is for HUMAN languages, and not for an extremely precise written language such as "Algebra". According to that, treating a number within an equation as any element of a sentence or as any part of speech part of sentence structure seems out-of-place; but still the question YOU ask suggests that you want to solve the equation for b, and to have a formula for b. Maybe this is a cultural thing; or maybe I have not seen a few new trends in mathematics education - I thought I would have seen this already if it were a normal way of discussing (subject, as part of numbers in an equation).

12. Mar 31, 2016

### SteamKing

Staff Emeritus
It's OK. You're only a Cat.

13. Mar 31, 2016

### Staff: Mentor

If the OP hadn't already seen these posts I would have deleted them. Giving too much help is a violation of the rules of this forum.

14. Mar 31, 2016

### micromass

Can you post what you think is the solution. It is very likely that what you think is incorrect.

15. Mar 31, 2016

### ProfuselyQuarky

Sorry! :(

16. Apr 1, 2016

### Einstein's Cat

Denouncing the mathematical abilities of others is obscenely unnecessary and by doing so, your personal interpretation of the extent of your ability is not enhanced. Thus, I advise you cease denouncing other's abilities and instead designate time to advancing your own.

17. Apr 1, 2016

### micromass

18. Apr 1, 2016

### Einstein's Cat

The square root of c^2 - a^2

19. Apr 1, 2016

### micromass

Exactly like I thought. That is the wrong solution. This is why I asked. Instead of berating me for being arrogant, you should trust my skills in knowing when a student like has a flaw in his/her thinking! I rarely go wrong there.

To give a hint where you go wrong: $\sqrt{b^2} \neq b$.

20. Apr 1, 2016

### ProfuselyQuarky

Mmm… @Einstein's Cat even if you’re personally annoyed with @micromass for showing how you are wrong, it would only benefit yourself to try at it again