Math Is Fun Forum

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Radicand Comes Out

Why does the radicand come out?

See here:

sqrt{(a + b)^2} = (a + b)

Why?

I can do it with anything.

Look here:

sqrt{(apple)^2} = (apple).

Why is that the case?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Radicand Comes Out

Square and square root are inverse operations. If you do one followed by the other you get back to where you started. Like double and half

B

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

e_jane_aran

Member

Registered: 2023-09-15

Posts: 10

Re: Radicand Comes Out

Why does the radicand come out?

See here:

sqrt{(a + b)^2} = (a + b)

Why is that the case?

Squaring and square-rooting are inverse operations (assuming the argument of the square root is non-negative). They undo each other. It is the same reason that 1 + 1 - 1 = 1 or (2*3)/3 = 2.

---

"They are fast. Faster than you can believe. Don't turn your back. Don't look away. And most of all, don't blink." -the 10th Doctor

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

Square and square root are inverse operations. If you do one followed by the other you get back to where you started. Like double and half

B

It makes sense, Bob. Ok. Cool.

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

Why does the radicand come out?

See here:

sqrt{(a + b)^2} = (a + b)

Why is that the case?

Squaring and square-rooting are inverse operations (assuming the argument of the square root is non-negative). They undo each other. It is the same reason that 1 + 1 - 1 = 1 or (2*3)/3 = 2.

Yes,  this is what Bob said. By the way, I left the other math forum after I was so rudely insulted by Jonah. Do not tell him that I am here. If you do, I will request for you to be banned from this site. He does not need to know where I am. Agree?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Radicand Comes Out

By the way, I left the other math forum after I was so rudely insulted by Jonah. Do not tell him that I am here. If you do, I will request for you to be banned from this site. He does not need to know where I am. Agree?

I started on the forum as an ordinary member and I helped a few folk with questions.  Then I was badly trolled because of an answer I gave.  I spent the next few days composing angry and sarcastic responses (in my head) . In the end I decided to just say nothing.

What I didn't know until later is the moderators were discussing the situation and had privately ordered the troll to retract what had been written.  They also discussed my behaviour and decided to ask me if I would become a moderator. 

If you had said nothing I wouldn't have known about this other forum incident at all.  Sometimes saying nothing is the best policy.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Radicand Comes Out

I started on the forum as an ordinary member and I helped a few folk with questions.  Then I was badly trolled because of an answer I gave.  I spent the next few days composing angry and sarcastic responses (in my head) . In the end I decided to just say nothing....

youre so kind and patient
thank you
<3

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

By the way, I left the other math forum after I was so rudely insulted by Jonah. Do not tell him that I am here. If you do, I will request for you to be banned from this site. He does not need to know where I am. Agree?

I started on the forum as an ordinary member and I helped a few folk with questions.  Then I was badly trolled because of an answer I gave.  I spent the next few days composing angry and sarcastic responses (in my head) . In the end I decided to just say nothing.

What I didn't know until later is the moderators were discussing the situation and had privately ordered the troll to retract what had been written.  They also discussed my behaviour and decided to ask me if I would become a moderator. 

If you had said nothing I wouldn't have known about this other forum incident at all.  Sometimes saying nothing is the best policy.

Bob

As the old saying goes: Silence is golden. It's ok for me that you know about my experience in not just one math forum but several forums. There are lots of angry folks in the world that really hate to see others happy doing something they enjoy.

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 241

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

---

Every living thing has no choice but to execute its pre-programmed instructions embedded in it (known as instincts).
But only a human may have the freedom and ability to oppose his natural robotic nature.
But, by opposing it, such a human becomes no more of this world.

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

actually, sqaure root is defined to be the positive answer

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

actually, sqaure root is defined to be the positive answer

Yeah, no kidding. Where is your math work? Seriously, I personally don't want to read a story about each problem posted. Just do the math. Get it?

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 241

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

actually, sqaure root is defined to be the positive answer

Based on this definition, you mentioned, you are totally right.

I just added what I know because in my designs, if I ended up with the equation:
x^2 - 9 = 0 
X^2 = 9
x = sqrt(9) = ±3
I had to consider both results.

But in case you believe that I do wrong, and I have to ignore always the negative result, please accept my apology.

Last edited by KerimF (2023-11-18 21:43:44)

---

Every living thing has no choice but to execute its pre-programmed instructions embedded in it (known as instincts).
But only a human may have the freedom and ability to oppose his natural robotic nature.
But, by opposing it, such a human becomes no more of this world.

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

actually, sqaure root is defined to be the positive answer

Based on this definition, you mentioned, you are totally right.

I just added what I know because in my designs, if I ended up with the equation:
x^2 - 9 = 0 
X^2 = 9
x = sqrt(9) = ±3
I had to consider both results.

But in case you believe that I do wrong, and I have to ignore always the negative result, please accept my apology.

No apology needed. Let's stay on the math course.

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

[addressed to KerimF] actually, sqaure root is defined to be the positive answer

Yeah, no kidding. Where is your math work? Seriously, I personally don't want to read a story about each problem posted. Just do the math. Get it?

what 'math' could i 'do' to correct the wrong info?
arent math definitions part of math?
but i'll leave bad info alone in future
sry

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

May I add...

sqrt{(a + b)^2} = ±(a + b)

like sqrt{(1 + 2)^2} = sqrt(9) = ±3

[addressed to KerimF] actually, sqaure root is defined to be the positive answer

Yeah, no kidding. Where is your math work? Seriously, I personally don't want to read a story about each problem posted. Just do the math. Get it?

what 'math' could i 'do' to correct the wrong info?
arent math definitions part of math?
but i'll leave bad info alone in future
sry

Also, stop saying sorry all the time. Understand? Just be normal, dude.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Radicand Comes Out

Let's not have an argument about what a poster says in helping. You have to let each person provide their help in their own way. If it doesn't help then you can ask for clarification or ignore it but please don't get angry. That doesn't help anyone. Remember my post about when I was trolled.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

Let's not have an argument about what a poster says in helping. You have to let each person provide their help in their own way. If it doesn't help then you can ask for clarification or ignore it but please don't get angry. That doesn't help anyone. Remember my post about when I was trolled.

Bob

I am not angry. Frustrated is a better word. I want to improve mathematically. This is not possible if members provides the entire solution. If I ask for a step by step solution, that's a different story.

zetafunc

Moderator

Registered: 2014-05-21

Posts: 2,436

Website

Re: Radicand Comes Out

Based on this definition, you mentioned, you are totally right.

I just added what I know because in my designs, if I ended up with the equation:
x^2 - 9 = 0 
X^2 = 9
x = sqrt(9) = ±3
I had to consider both results.

But in case you believe that I do wrong, and I have to ignore always the negative result, please accept my apology.

Actually, you have the right idea, it's just that the ± symbol needs to come slightly earlier. Instead of:

you want to say:

And what amnkb is saying is that

.

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 241

Re: Radicand Comes Out

Actually, you have the right idea, it's just that the ± symbol needs to come slightly earlier. Instead of:

you want to say:

And what amnkb is saying is that

.

Just to give an idea about my nature, I respect always other's views and knowledge no matter if they sound right or wrong to me.
And when I contact others, I simply say what I know while I understand fully that they may have their good reasons not to accept everything I say/know.

---

Every living thing has no choice but to execute its pre-programmed instructions embedded in it (known as instincts).
But only a human may have the freedom and ability to oppose his natural robotic nature.
But, by opposing it, such a human becomes no more of this world.

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Radicand Comes Out

Copy. Understood.