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HyperComplexxx

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Do you remember your answer for the red light q - binomial probability.

and did you do the last question 7b) tan, alpha stuff
prob i got 0.36, hope its right :S
the tan alpha one
i. show alpha = Tan-1(H/x) - Tan-1(h/x)
ii. diff and let = 0 to find max alpha (it said no testing so no test)
iii. tan both sides and simplify x^2 = Hh/2sqrt(Hh)
 

Dylanamali

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sweet i got 0.36 aswell

I got part 1 im preety sure, just do simultaneous equations.

ah part ii and iii f'ed em up =/
 

Dylanamali

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What was the circle geo answer...

The proof for congruency, i had AAS.
 

Drongoski

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(2+root3)^3 - 15 (2+root3) + 4

btw, it's a sharp calculator.
Now we can see why you had problem. Yr Sharp calculator probably gave answer

That's for all intent and purposes zero. When your calculator computed , an irrational number it had to round the value to say 12 decimal places, so there is a discrepancy from the "true" value pf 1.73205 . . . . (forever) - so you can never represent the exact value with a finite number of digits. That's why overall you had a small "nonzero" final value.
 

muzeikchun852

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the tan alpha one
i. show alpha = Tan-1(H/x) - Tan-1(h/x)
ii. diff and let = 0 to find max alpha (it said no testing so no test)
iii. tan both sides and simplify x^2 = Hh/2sqrt(Hh)
i. you look at the triangle that were given. and substitute the angles corresponded to it.
Tan-1(H/x) - Tan-1(h/x)
= alpha + theta - theta
= alpha

Now we can see why you had problem. Yr Sharp calculator probably gave answer

That's for all intent and purposes zero. When your calculator computed , an irrational number it had to round the value to say 12 decimal places, so there is a discrepancy from the "true" value pf 1.73205 . . . . (forever) - so you can never represent the exact value with a finite number of digits. That's why overall you had a small "nonzero" final value.
okay. i'm throwing my sharp and swapping over to casio after hsc.
 
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HyperComplexxx

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What was the circle geo answer...

The proof for congruency, i had AAS.
yea same
i spent like friggen 10min on the 1 marker (ii) of the circle question, i didn't read carefully and never knew the triangles were given to be congruent
 

Dylanamali

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Did the actually say that the triangles were congruent? (The two mini triangles)
In ii) I actually proved they were congruent/isoscles then did my proof.
 

muzeikchun852

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Did the actually say that the triangles were congruent? (The two mini triangles)
In ii) I actually proved they were congruent/isoscles then did my proof.
you use the answer in (i) and then the angle on the left hand side will be the same as the corresponding angle in the congruent triangle. after that vertically opposites angles and finish.
 

brettymaccc

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I used RHS and proved alpha to be 45, giving the angle in the semicircle to be 2alpha, therefore making it a right angle. :s
 

jamesfirst

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What was the circle geo answer...

The proof for congruency, i had AAS.
All my friends got AAS


I was the only one who did SAS...


and did you do the last question 7b) tan, alpha stuff


I got 7 b) iii) definitely correct. But I'm not sure about 7 b) ii). I got the answer but I come some other shit at the end like . x^2 = hx + Hh + blah blah I dk


So I just made the big chuncky shit at the end = 0 and I did hence x^2 = blah blah blah


looooooooooooooool hope I get a full mark for that.
 

taeyang

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so what were parts (a) and (b) for q7 and q6 of the test? was there anything that was very tricky?
 

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