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So given ABCD, A(0,0,0) B(1,1,0) , C(1,-1,1) ,D, (3,0,1) I need to find the volume of the tetrahedron now I know that the volume of the tetrahedron = 1/6 detA But the determinat of this matrix is 0 so that's it I have the volume = 0 or I didn't calculate it right

Taw Taw
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1 Answers1

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The determinant is

1*(-1)*1 + 1*1*3 - 1*1*1 = -1 + 3 - 1 = 1

I used the Sarrus Rule to calculate it. The other terms are zero.

So yes, you didn't calculate it right.

Frank Puffer
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  • Now I don't have the same answer I used the scalar product and the answer is 1/6 and according to your answer is -1/6! – Taw Taw Nov 11 '18 at 19:40
  • now I have different answers by determinats according to your answer it's -1/6 , and by the scalar product 1/6! – Taw Taw Nov 11 '18 at 19:51
  • @TawTaw: The determinant I calculated is 1, so the volume is 1/6. Aside from that, a volume can not be negative. – Frank Puffer Nov 11 '18 at 19:57