Ellipse

2009-08-22 7:23 pm
How to prove graphically that the equation of ellipse is:
x = a cos t
y = b sin t


更新1:

Please provide the proof anyway if you think it is simple to prove graphically.

回答 (3)

2009-08-23 2:34 am
✔ 最佳答案
In fact, the standard form of equation of an ellipse is:

x2/a2 + y2/b2 = 1, where a and b are any real numbers with a and b =/= 0

Put x = acost and y = bsint into L.H.S.

Therefore,

L.H.S.

= (acost)2/a2 + (bsint)2/b2

= a2cos2t/a2 + b2sin2t/b2

= cos2t + sin2t

= 1

= R.H.S.

So, we finished the proof.
參考: Physics king
2009-08-23 12:36 am
Graphs do not provide any rigorous proof in mathematics.
2009-08-22 10:20 pm
Graphically? It won't be a proof!


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