Reflection Theory (2 Viewers)

[Implying]

equiangular =/= congruent

PQ was common. they were congruent

 

[SImon05089]

i think hup meant equiangular as in 3 equal angles, pq is a side

 

[4025808]

well I was lucky, because I just used it
thank god for this question

 

[khfreakau]

You could have stated the perpendicular from the vertex to the base bisects the base in an isos triangle. Much quicker

yeah this, i did it using this method. i think i was lucky in that i remembered what the reflection property was, they rarely ask for those obscure dot points.

 

[zhuang281]

Only got this question because i learnt what the reflection theory was in physics.

 

[clementc]

How did you know it was an isosceles triangle though?

 

[khfreakau]

How did you know it was an isosceles triangle though?

altitude which bisects the base of a triangle means that it is isosceles.

 

[clementc]

but arent you trying to prove that the altitude bisects the triangle base?

 

[tywebb]

How about the reflection property for the hyperbola?

Has this been asked before in an HSC exam or trial exam?

I'm interested because at the last MANSW conference there were people from the Board of Studies who were asked about the reflection property and has it been asked in exams before. It seems that it has for the ellipse but not the hyperbola. I'm not sure if this is true however.

It has recently been announced that the state ministers have endorsed the new f-10 syllabus and so maybe the extension 2 syllabus's days are numbered. When this happens exam committees for the last years of a syllabus have to find questions on aspects of the syllabus that have NEVER been asked.

I think that in the next few years we really must focus on these aspects.

 

[khfreakau]

but arent you trying to prove that the altitude bisects the triangle base?

oh right my bad i used this result for part ii, not i haha. in i i equated the tans of the angles to show that they were equal, and then said in ii that altitude which bisects the base means the triangle is isosceles, so PR=SP

 

[clementc]

fml of course .__. ohhh now seems so obvious lol