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#26 Re: Help Me ! » Exponential Equation » 2024-05-26 18:30:30

Bob wrote:

Normally I'd say yes  but if you do the x cancel out and you're left with an inconsistency.

Just checking Wolfram Alpha

Back again. As suspected WA gives x=0 as the only real solution.

Bob

Now that we know that x = 0 is the only real solution, how do we find x?

#27 Re: Help Me ! » Number Raised To Itself » 2024-05-26 18:29:08

Bob wrote:

When you encounter repeat indices like this the rule is work from the top down.

So 3^(3^27)=3^(3×3×3×....3)

That's one BIG number.

Bob

Thanks. Yes, it's a huge number that we can write using scientific notation.

Agree?

#28 Re: Help Me ! » Prime Numbers » 2024-05-26 18:27:59

Bob wrote:

There are no patterns nor formulas for this, so I think you just have to list and count.

Keep the list: it'll be useful later.

Bob

I am not going to make such a list but thanks.

#29 Help Me ! » Rationalize Denominator » 2024-05-26 09:58:12

mathxyz
Replies: 7

I am having a hard time with the following problem:

5 ÷ [cuberoot(2)]

#30 Help Me ! » Seeking Formula » 2024-05-26 06:27:52

mathxyz
Replies: 2

What is the formula for determining the 7th number on the 20th row of the famous Pascal Triangle?

#31 Help Me ! » More Prime Numbers » 2024-05-26 06:24:31

mathxyz
Replies: 2

Which prime numbers under 100 are 8 less than a perfect square?

#32 Help Me ! » Exponential Equation » 2024-05-26 06:23:04

mathxyz
Replies: 4

How is this done?

Solve for x.

3^(9x) = 9^(3x)

I am thinking about taking the log on both sides.

You say?

#33 Help Me ! » Number Raised To Itself » 2024-05-26 06:19:26

mathxyz
Replies: 4

What is the best and fastest way to raise a number to itself several times?

Sample:

What is 3^(3)^(3)^(3)?

#34 Help Me ! » Prime Numbers » 2024-05-26 06:16:46

mathxyz
Replies: 3

How many prime numbers are there between 1 and 100?
Is there a quick way to find these prime numbers?

#35 Re: Help Me ! » Absolute Value Notation » 2024-05-26 02:46:07

Bob wrote:

That looks OK to me. If t=5.1 , abs(t) > 5 and its certainly more than 5 from the origin.  If t = 4.9 it isn't.

Bob

Ok.

#36 Re: Help Me ! » Write Expression Without Absolute Values » 2024-05-26 02:44:33

Bob wrote:

Of course. No other way.  The positive value of a calculation is the same if its positive or zero and otherwise switch the sign.

Bob

Ok.

#37 Re: Help Me ! » Solve For a » 2024-05-26 01:46:29

Bob wrote:

Here's a useful algebraic trick. It will help you to see if your working is right at each step. Choose values for a and b and work out what that makes R. Then use your values of R and b to see if the final value for a is the one you started with.


Normally I wouldn't choose the same for a as for b but your answer didn't look right. I needed a quick check.

I put a = b = 1/2 at the start and got R = 1.

R = 1 and b = 1/2 doesn't give a = 1/2.

I think it's the first R = where the trouble starts. That fraction is the wrong way up. But I think a new approach will get you to the answer more quickly.   Make 1/a the subject and when you've simplified to one fraction invert it for a.

Bob

Ok.

#38 Re: Help Me ! » Absolute Value Notation » 2024-05-25 20:32:20

Bob wrote:

a , b and c are correct.

d ) If you subtracted 5 from t the result would be positive.

Bob

A friend told me that the answer is | t | > 5.
How can this be?

#39 Re: Help Me ! » Write Expression Without Absolute Values » 2024-05-25 20:30:46

Bob wrote:

Each one contains a calculation.  If the result is positive or zero then the absolute sign is redundant; you can simply leave it out. If the result is negative then the result must be made positive (by multiplying by minus 1).  In all of these you can decide whether the result is + or - .

Bob

Can the definition of absolute value be used to solve these?

#40 Help Me ! » Solve For a » 2024-05-25 20:22:16

mathxyz
Replies: 2

Given R = 1/[(1/a) + (1/b)].

Let me see.


LCD for [(1/a) + (1/b)] is ab.


I get (b + a)/(ab).


R = (b + a)/(ab)

(ab)R = b + a

abR - a = b

a(bR - 1) = b

a = b/(bR - 1)

You say?

#41 Help Me ! » Absolute Value Notation » 2024-05-25 16:36:07

mathxyz
Replies: 4

Rewrite each of the following statements using absolute value notation.


(a) The distance between 12 and 5 is 17.


| 12 - 5 | = 17



(b) The distance between xand 2 is 4.



| x - 2 | = 4



(c) The distance between x and 2 is less than 4.


| x - 2 | < 4


(d) The number t is more than five units from the origin.


| t | + 5


Is any of this right?

#42 Help Me ! » Write Expression Without Absolute Values » 2024-05-25 16:30:29

mathxyz
Replies: 4

Rewrite each expression in a form that does not contain absolute values.
How is this done? 


(a) | pi - 4 | + 1


(b) | x - 5 | given that x > or = 5


(c) | t - 5 | given that t < 5.

#43 Help Me ! » FOR BOB: Equitable Mathematics » 2024-05-25 16:02:04

mathxyz
Replies: 3

I have deleted the posts in this thread as you have broken our rules by making  a personal attack on another member.

I have also removed your signature as I find it equally offensive  Any further infringements and you will be banned. Bob

#45 Help Me ! » Express R As Rational Expression » 2024-05-25 08:32:56

mathxyz
Replies: 2

Given R = (1/a) + (1/b) + (1/c), express R as a rational expression.


Let me see.


LCD on left side is abc.


So, abc ÷ a = bc.

Then,  abc ÷ b = ac.

Finally, abc ÷ c = ab


On the right side, I get (bc + ac + ab)/(abc), which is a fraction in terms of a, b, and c.


I say R = (bc + ac + ab)/(abc) is the answer.


You say?

#46 Re: Help Me ! » How Many Math Questions Per Chapter? » 2024-05-25 08:22:24

Bob wrote:

Yes. If you can get a few right it suggests you've mastered the why.

Bob

Ok.

#47 Re: Help Me ! » Quadratic equation » 2024-05-24 21:47:33

Irene wrote:

Tanx

No problem. You're welcome.

#48 Re: Help Me ! » How Many Math Questions Per Chapter? » 2024-05-24 21:45:11

Bob wrote:

Be guided by your success with practice questions.  If you're getting on well then move on; if you're having difficulties , you need to do more.

Bob

Isn't it better to understand math than to solve hundreds of problems like a robot? In other words, knowing the WHY is more important than quantity.

You say?

#49 Help Me ! » How Many Math Questions Per Chapter? » 2024-05-24 16:00:58

mathxyz
Replies: 4

How many math questions per chapter should a person answer when doing a self-study of mathematics? If I answer every question, I will never complete the textbook.

You say?

#50 Re: Help Me ! » Quadratic equation » 2024-05-24 15:59:13

Irene wrote:

How can i get his website??? Or his YouTube channel? Thanks

I don't know his website. However, just type his name using YouTube search. It will take you to his channel.

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