Preliminary mathematics marathon (3 Viewers)

[edmundsung]

new question thx

 

[ohexploitable]

Re: new question thx

a)

ΔBED ||| ΔBAC (SAS)

.: BE:BA = BD:BC

BX = 1/2 BD (given)
BY = 1/2 BC (given)

.: BX:BY = BD:BC

but BE:BA = BD:BC

.: BE:BA = BX:BY

.: ΔBEX ||| ΔBAY (SAS)

--------------------------------------------------

b)

Converse of intercepts on transversals.

 

[YaMiTe]

whats the hardest trigonometry questions ever!!
i need one so i can watch my teacher suffer in pain by not being able to solve it
thanks

 

[edmundsung]

Re: new question thx

a)

ΔBED ||| ΔBAC (SAS)

.: BE:BA = BD:BC

BX = 1/2 BD (given)
BY = 1/2 BC (given)

.: BX:BY = BD:BC

but BE:BA = BD:BC

.: BE:BA = BX:BY

.: ΔBEX ||| ΔBAY (SAS)

SAS is the condition for congruent triangles, but not similar triangles. @@

 

[hscishard]

Re: new question thx

SAS is the condition for congruent triangles, but not similar triangles. @@

The sides are similar.

 

[edmundsung]

Re: new question thx

The sides are similar.

it is "ratio of 2 sides and included angle", isn't it?

 

[ohexploitable]

Re: new question thx

SAS is the condition for congruent triangles, but not similar triangles. @@

Cambridge uses that notation for similarity proofs. Cambridge wins

 

[edmundsung]

Re: new question thx

Cambridge uses that notation for similarity proofs. Cambridge wins

then im just wondering if "SAS" is one of the notations for congruent triangles proofs used in Cambridge

 

[ohexploitable]

Re: new question thx

SAS is used in both congruency and similarity proofs, in congruency proofs it means, "two sides equal and included angle equal", in similarity it means, "two sides in proportion and included angle equal".

 

[ohexploitable]

Gradient of chord = 4-1/2--1 = 1

x=t y=t^2
y=x^2
y'=2x

When y'=1, x = 0.5
f(0.5)=0.25

Line of tangent t y= x-0.25
Midpoint of PQ = (2+0.5)/2 ,(4+-2)/2 = (1.25,1)

Sub Midpoint into tangent line, LHS=RHS
Therefore tangent T bisects PQ
Thats the shitness of show questions.
What's the other way?

It was given that tangent T bisects QR, the question asked to prove tangent T is parallel to PQ.

 

[edmundsung]

Re: new question thx

SAS is used in both congruency and similarity proofs, in congruency proofs it means, "two sides equal and included angle equal", in similarity it means, "two sides in proportion and included angle equal".

i get it now thank you very much

 

[hscishard]

It was given that tangent T bisects QR, the question asked to prove tangent T is parallel to PQ.

Lol omg.
Gradient of chord = 4-1/2--1 = 1

x=t y=t^2
y=x^2
y'=2x

When y'=1, x = 0.5
f(0.5)=0.25

Line of tangent t y= x-0.25
Midpoint of PQ = (2+0.5)/2 ,(4+-2)/2 = (1.25,1)
Sub Midpoint into tangent line, LHS=RHS
Therefore y=x-0.25 is the tangent.
Gradients are equal, therefore parallel?

Changed a few words. That enough but?

 

[ohexploitable]

New Question:

Differentiate the Folium of Descartes with parameter a=1.

Folium of Descartes - Wikipedia, the free encyclopedia

 

[fullonoob]

 

[hscishard]

New Question:

Differentiate the Folium of Descartes with parameter a=1.

Folium of Descartes - Wikipedia, the free encyclopedia

This isn't prelim. Prelims don't do that kind of differentiation

 

[fullonoob]

yes it is prelim. It is called implicit

 

[hscishard]

yes it is prelim. It is called implicit

That's only for 4 unit..

 

[shaon0]

yes it is prelim. It is called implicit

You're correct, i did a q regarding diff of folium of descartes in yr11.

 

[hscishard]

WTF. My school is delayed.

 

[ohexploitable]

This isn't prelim. Prelims don't do that kind of differentiation

It's in Year 11 Cambridge.