help with problem (1 Viewer)

[pl4smaa21]

Does anyone know how to do (a) (b) and (c), thanks in advance

 

[pl4smaa21]

aight man thnx i have the old cambridge 3u book cuz i got it at the end of year 10 from school to like preview some of the material ig I posted this becuz it seemed like a bit of a tough problem and I couldn't solve fully so thanks very much.

 

[pl4smaa21]

u know when the proof for c. presented here first appeared? 1880

Journal de mathematiques elementaires et speciales, 1880, p. 538

View attachment 46267
View attachment 46268
also attached are 3 articles on c.

Hajja, M., A Short Trigonometric Proof of the Steiner-Lehmus Theorem, Forum Geometricorum Volume 8 (2008) 39–42.

Sauvé, L., The Steiner-Lehmus theorem, Crux Math., 2 (1976) 19–24.

Trigg, C.W., A bibliography of the Steiner-Lehmus theorem, Crux Math., 2 (1976) 191–193.

damn man u putta lotta effort into this more than I could have hoped for thanks. and yea that's kinda interesting that this small ext. problem has a lotta history

 

[pl4smaa21]

hmm okay i couldn't have guessed there were over 80 ways to do that wow. So like they rely heavily on proof by contradiction. I only know year 10 math and a bit of year 11 but i do remember that proof by contradiction is taught in Ext 2 right?

 

[pl4smaa21]

i think it is worth pointing out that when the old cambridge 3 unit year 12 text was published in 2000, no direct proof was known for the c.

old Cambridge was published from 2000??? Damn this textbook I got is a relic is soo colorful tho esp. when compared to the depressing black and white in the new 4u cambridge textbook lol

 

[joeystarbank]

this problem is easy

 

[svad]

bye how did this start with a math q and end up at a history lesson