Help In Understanding. (1 Viewer)

Shadowless

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Question: P05Q3DII.png

Answer: P05A3DII.png

I don't understand why.

I've realised that when I did this problem I did what the solution required of me (i.e. using quadratics and using the discriminant, etc, etc. because the question prior to this set me up a quadratic obviously) but I've never understood why.

Could someone explain this solution to me?

EDIT: PART TWO OF THE QUESTION NOT PART ONE.
 
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Nws m8

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product of ratio of intercepts brah
 

HeroicPandas

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If "x" is a length then it must be REAL, to find real roots we use DELTA greater or equal to zero

Taking the equality of the inequality for the min distance
 

Nws m8

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If "x" is a length then it must be REAL, to find real roots we use DELTA greater or equal to zero

Taking the equality of the inequality for the min distance
pretty much this
 

HeroicPandas

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We can't have unreal "x" values because we are looking at LENGTHS, since we don't know how many VALUES of "x", we use DELTA is greater or equal to zero

We cant use DELTA greater than zero

^ I think i just confused myself
 
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Shadowless

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Hmm. Okay. I get it now. Thanks.

Next...

Question: P05Q4CI.png

Answer: P05A4CI.png

My question is, let's say once we find 'x' can we just do the following?

As x = ???, subbing this value into equation 1 will yield y = ??? (we know the value for y as this is a show question and they already gave it to us).

Then write...

Therefore the coordinate of point R is (X,Y) [by looking at the question].
 

HeroicPandas

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Hmm. Okay. I get it now. Thanks.

Next...

Question: View attachment 26807

Answer: View attachment 26808

My question is, let's say once we find 'x' can we just do the following?

As x = ???, subbing this value into equation 1 will yield y = ??? (we know the value for y as this is a show question and they already gave it to us).
Thats risky, I wouldn't do that xD
Just work it out
 

HeroicPandas

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If u dont entirely get the first question on that circle question, just use calculus, let f(x) be blah blah, differnetiaite equate etc
 

Nws m8

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Hmm. Okay. I get it now. Thanks.

Next...

Question: View attachment 26807

Answer: View attachment 26808

My question is, let's say once we find 'x' can we just do the following?

As x = ???, subbing this value into equation 1 will yield y = ??? (we know the value for y as this is a show question and they already gave it to us).

Then write...

Therefore the coordinate of point R is (X,Y) [by looking at the question].
SImple question bro, equate two equations and find x and y ....
 

Shadowless

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If u dont entirely get the first question on that circle question, just use calculus, let f(x) be blah blah, differnetiaite equate etc
LOL that's what I did, but it seemed too much working out compared to the answers, so yeah.
 

Shadowless

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SImple question bro, equate two equations and find x and y ....
Are you even looking at my 'question'? LMAO

Most of my 'problems' in 3U isn't that I don't know how to solve, it's more 'what's the quickest and most efficient way of doing the question' if you get what I mean.
 

Nws m8

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Are you even looking at my 'question'? LMAO

Most of my 'problems' in 3U isn't that I don't know how to solve, it's more 'what's the quickest and most efficient way of doing the question' if you get what I mean.
lol that's the way I do it, it is quick ...
 

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