WHY there is holiday

On the contrary --- I've got work to do!!!

 

Keep in mind that the goal is to relate the limits on Req in relation to the values of R1 and R2. We aren't looking for the limits on Req for all values of R1 and R2, but for the specific values they happen to be.

So we can't just say that R1 could be zero ohms. It can't. R1 is whatever R1 is.

Let's use an example to illustrate the practical point.

You have two resistors, R1 = 1800 Ω and R2 = 2200 Ω. Without batting any eye or doing any more work than dividing by two, you know that the parallel combination of these two resistors has to be more than 900 Ω (half the smaller one) but can't be more than 1100 Ω (half the larger). The question that I posed is aimed at establishing this relationship. Picking another two values, R1 = 1800 Ω and R2 = 8200 Ω. As before, we know that the value has to be more than 900 Ω and less than 4100 Ω, but the other part of the question allows us to know that the largest it can be is 1800 Ω (the smaller of the two). Again, the point of the question is to show that this is the case, instead of just accepting it on faith.

Thanks, @WBahn !!! --- The more I thought about the exercise - the more it seemed I may be misapprehending its intent -- thus my (as it turns out well advised) decision to 'pass' on its presentation

Best regards
HP

 

Flying was a hobby for me -- though I always wanted to get my instructor's ticket so that at least others could pay for most of my flight time. I'm definitely not a rich man and flying is sufficiently expensive that I never was able to do a lot of it. I only have a little over 300 hours pilot-in-command time. I haven't flown in over a decade and, due to health issues, there's a good chance I will never fly pilot-in-command again.

For whatever reason @RRITESH KAKKAR Seems unfamiliar with the concept of 'hobbies' -- Perhaps it owes to cultural differences???

Best regards
HP

 

@RRITESH KAKKAR

I'll chat with you in ≈ 34 hours from the time stamp on this post --- In the meantime please work on @WBahn 's exercise bearing mind that he is a real teacher!

When I return I can show you how to manipulate expressions containing inequalities and absolute values - would you be interested in that???

Best regards
HP

 

Hello,

Ever thought on imaginairy numbers?
Bertus

RRITESH KAKKAR If you think about imaginary numbers in everyday experience you can understand things like
electrical reactance
mechanical elasticity and other static force and reaction
principal like of a bank loan

And like that! Imaginary numbers aren't really imaginary at all! That's misnomer cuz ppl run out of names for concepts then just get silly like they did when named the types of quarks

Now I give you three exercises that I say you already know enough to do!

1 If complex number is written in rectangular form like 32+12i which you can think of like 32+(-144)^.5
What are the angle and magnitude when you think about it as vector?

2 If a rectangle measures 10i meters by 20i meters it has area of NEGATIVE 200 meters! Tell us what is implication of negative area?

3 If a rectangle measures (5+10i) meters by (7-4i) meters it has area of (75+50i) meters. Tell us what is implication of complex area? I give you help with this one only to say that 25*(13)^.5 meters is NOT its area!

RRITESH KAKKAR at first I skeptical about HP and Wbahn helping you out Now I think you are eager student after all! Plz don't stop learning!

HP Don't you dare give him answers with your TMI hints! I say you can help him if he doesn't understand questions but that's it!

 

RRITESH KAKKAR HP said for me to see if you doing your math studies while she's away and I see you logged but not doing work so I'm going to inform on you, you little truant!

 

So I world's worst teacher so I leave b4 you put wormy apple on my desk but I say better get busy

 

Hello,

Ever thought on imaginairy numbers?
https://en.wikipedia.org/wiki/Imaginary_number
http://www.mathsisfun.com/numbers/imaginary-numbers.html

Bertus

why, it is ?
i × i = -1 = √-1*√-1=1 (it should be +ve)
√-1=i

 

RRITESH KAKKAR HP said for me to see if you doing your math studies while she's away and I see you logged but not doing work so I'm going to inform on you, you little truant!

while she's away is, she was lady i was not familiar.
let move to work.

 

Yes, if you are willing to use both values in the bound, you can come up with a tighter bound.

This one might be a good one to use to show RRITESH the idea here.

Regardless of whether R1 is bigger than R2, we know that, since anything squared is non-negative, that

0 < (R1-R2)²

If we multiply this out, we get

0 < R1² - 2R1R2 + R2²

If we add 4R1R2 to both sides we get

4R1R2 < R1² + 2R1R2 + R2²

The right hand side is simply

4R1R2 < (R1 + R2)²

Dividing both sides by (R1 + R2) we get

(4R1R2)/(R1 + R2) < (R1 + R2)

and dividing both sides by 4 we get

(R1R2)/(R1 + R2) < (R1 + R2)/4

The left hand side we now recognize as being Req, so

Req < (R1 + R2)/4

Of course, Req < R1 becomes the tighter bound as soon as R2 > 3R1

What was this?

 

Flying was a hobby for me -- though I always wanted to get my instructor's ticket so that at least others could pay for most of my flight time. I'm definitely not a rich man and flying is sufficiently expensive that I never was able to do a lot of it. I only have a little over 300 hours pilot-in-command time. I haven't flown in over a decade and, due to health issues, there's a good chance I will never fly pilot-in-command again.

What was salary per 300hours?

 

RRITESH KAKKAR If you think about imaginary numbers in everyday experience you can understand things like
electrical reactance
mechanical elasticity and other static force and reaction
principal like of a bank loan

And like that! Imaginary numbers aren't really imaginary at all! That's misnomer cuz ppl run out of names for concepts then just get silly like they did when named the types of quarks

Now I give you three exercises that I say you already know enough to do!

yesterday, i got √-1=i
in everyday experience
where?

 

1 If complex number is written in rectangular form like 32+12i which you can think of like 32+(-144)^.5
What are the angle and magnitude when you think about it as vector?

32+12i=32+(-144)^2

i have done in class something like tanQ=12/32
so, Q=20.5*degree
c=√32²+12²=34.17

 

while she's away is he lady if was not familiar.
let move to work.

HP is woman, I not sure about lady!

I give you three problems to solve on post 705 and Wbahn gave you problem of limits on paralleling two resistors! I can't coach you all night like HP cuz I have to live my life! HP wanted me to give you encouragement to do studies so here I am Have good luck! HP says she maybe back on here tomorrow

 

1 If complex number is written in rectangular form like 32+12i which you can think of like 32+(-144)^.5
What are the angle and magnitude when you think about it as vector?

2 If a rectangle measures 10i meters by 20i meters it has area of NEGATIVE 200 meters! Tell us what is implication of negative area?

3 If a rectangle measures (5+10i) meters by (7-4i) meters it has area of (75+50i) meters. Tell us what is implication of complex area? I give you help with this one only to say that 25*(13)^.5 meters is NOT its area!

2 If a rectangle measures 10i meters by 20i meters it has area of NEGATIVE 200 meters! Tell us what is implication of negative area?

 

http://www.allaboutcircuits.com/tex...rent/chpt-2/introduction-to-complex-numbers/#

i found this tutorial.

 

How to add this source?

 

http://www.allaboutcircuits.com/tex...rent/chpt-2/introduction-to-complex-numbers/#

i found this tutorial.

RRITESH I thought out question 2 & 3 in way so you can't just look them up. You should think what negative and complex area means cuz if you discover meaning like that you remember for good! Also it's fun! Question 1 is just rectangular to polar conversion so you'll know it from k-12

RRITESH I can't be back anymore tonight. PLZ do best you can!

 

2 If a rectangle measures 10i meters by 20i meters it has area of NEGATIVE 200 meters! Tell us what is implication of negative area?

3 If a rectangle measures (5+10i) meters by (7-4i) meters it has area of (75+50i) meters. Tell us what is implication of complex area? I give you help with this one only to say that 25*(13)^.5 meters is NOT its area!

2 If a rectangle measures 10i meters by 20i meters it has area of NEGATIVE 200 meters! Tell us what is implication of negative area?
how to do?

 

What was salary per 300hours?

I didn't get paid to fly, I PAID to fly. The aircraft rental, for most of the time, was $68/hour (that was for a T-41B from the aeroclub at the Air Force Academy -- sweet airplane). When I was training the cost of an instructor was an additional $24/hr. The 300 hours was spread out over nearly 30 years (mostly in three concentrated groups of about a year a piece).