So i am struggling with some calc 3...i have show that A(1,1,4), B(3,7,7), and C(7,5,-8) are the vetices of a right triangle...

Question

anonymous · Answer

I know that B dot C is 0 which means that the angle between them is 90 degrees just not sure how to show that A is the hypotenuse

jamesj · Answer

No, not quite.  A, B and C are the 'corners', the vertices, not the sides.

The three sides are AB (i.e., A - B) , BC (i.e., B - C)  or CA (i.e., C - A).  

If the triangle ABC is a right triangle, two of the sides will be perpendicular.  Hence one of the dot products AB.BC or AB.CA or BC.CA will be zero.

Just calculate them until you find one that is, as we know from the question one of them will be.

Have you got it now?

anonymous · Answer

yeah, thank you!

jamesj · Answer

Please give me a 'good answer' ;-)

anonymous · Answer

sorry im new to this thing

jamesj · Answer

np

anonymous · Answer

are you good at calc 3? I am also having issues with a couple other problems, one is computing the arclength paramaterization and the other has to do with tensions in wire