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/sci/ - Science & Math


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File: 37 KB, 500x400, 24749_377079797554_565062554_3890291_7964457_n.jpg [View same] [iqdb] [saucenao] [google]
1783656 No.1783656 [Reply] [Original]

Why is 2/(√5-1) ,(√5+1)/2

Also could you explain how its done,many thanks

>> No.1783663

2/(√5-1)=2(√5+1)/(√5-1)(√5+1)=2(√5+1)/5-1=(√5+1)/2

>> No.1783666

quadratic expansion

>> No.1783694

>>1783663
I dont get what you mean

>> No.1783704

>>1783694
why?

>> No.1783708

BeastUK was such a fucking douchebag. He is the one that troll tipped me over that which convinced me to stop lurking /b/

He's a bald white supremecist fat & pasty limey faggot who thinks way too highly of himself.

I hope he gets raped by a pack of pakistani immigrants.

>> No.1783715

<div class="math">\frac{2}{\sqrt{5}-1} = \frac{2(\sqrt{5}+1)}{(\sqrt{5}-1)(\sqrt{5}+1)} = \frac{2(\sqrt{5}+1)}{\sqrt{5}\sqrt{5}-\sqrt{5}+\sqrt{5}-1} = \frac{2(\sqrt{5}+1)}{5-1}= \frac{2(\sqrt{5}+1)}{4)= \frac{(\sqrt{5}+1)}{2}</div>

>> No.1783716
File: 14 KB, 1008x630, halp.png [View same] [iqdb] [saucenao] [google]
1783716

Pic related,

i dont understand the steps

>> No.1783720

<div class="math"> \frac{2}{\sqrt{5}-1} = \frac{2(\sqrt{5}+1)}{(\sqrt{5}-1)(\sqrt{5}+1)} = \frac{2(\sqrt{5}+1)}{\sqrt{5}\sqrt{5}-\sqrt{5}+\sqrt{5}-1} = \frac{2(\sqrt{5}+1)}{5-1}= \frac{2(\sqrt{5}+1)}{4})= \frac{(\sqrt{5}+1)}{2}</div>

>> No.1783726

$\frac{a}{b+c}=\frac{a(b-c)}{(b+c)(b-c)}\\frac{a(b-c)}{b^2-c^2}

>> No.1783736

>>1783720
>>1783663

Big thanks for the help i really appreciate it.

>> No.1783741

>>1783726
how to use jsmath?

>> No.1783755

$\frac{a}{b+c}=\frac{a(b-c)}{(b+c)(b-c)}\\frac{a(b-c)}{b^2-c^2}$

>> No.1783819

how would i do something like √8/(√2-1) then? times both by (√2-1)?