"㊣→咪走寶!!!!MATHS,只此1題★唔好汁書)_好趕+

2011-02-27 4:55 am
***Please show all workings, even very easy!!
It's worth to answer, u gonna get Double Score if your answer is perfect!!!
so u can get 20 if your answer is attempted!!!

Q1)
x=(t^2)-2t ----- equation1
y=(t^2)+2 ----- equation2Ans: (y-x)^2-4(2y-x)+12=0 Q2)
x=3(t+1/t) ---- equation1
y=4(t-1/t) ----- equation2Ans: (x^2)/36 - (y^2)/64 = 1

回答 (1)

2011-02-27 5:11 am
✔ 最佳答案


Well, you can attempt in the ways below by trying to eliminate the existence of "t" in two equations and combine them into one:


1) x = t^2 - 2t and y = t^2 + 2

Hence, x = ( y - 2 ) - 2t

( x - y + 2 ) = -2t

( x - y + 2 )^2 = 4t^2 = 4( y - 2 )

[ ( x - y ) + 2 ]^2 = 4( y - 2 )

( x - y )^2 + 4( x - y ) + 4 = 4y - 8

( x - y )^2 + 4( x - 2y ) + 12 = 0

( y - x )^2 - 4( 2y - x ) + 12 = 0
=========================


2) x = 3( t + 1/t )

x^2 = 9( t^2 + 2 + 1/t^2 )

y = 4( t - 1/t )

y^2 = 16( t^2 - 2 + 1/t^2 )

Solve by elimination method:

16 x^2 - 9 y^2

= 144 ( t^2 + 2 + 1/t^2 ) - 144 ( t^2 - 2 + 1/t^2 )

= 576

Hence, divide both sides by 576, we have

x^2/36 - y^2 / 64 = 1
=================


Hope I can help you.

參考: Mathematics Teacher Mr. Ip


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