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define new vector

asked 2015-03-15 21:15:30 -0500

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hi i'm new in sage , I have two vectors

v1=vector([8,-10,12])
v2=vector([9,4,-6])

i want to create a third one which is parallel with v1 and also the scalar product of v2 and v3 is equal to 1440

(x,y,z)=var('x,y,z')
v3=vector([x,y,z])

solve([v1.dot_product(v3)==1440,v2.cross_product(v3)==0],x,y,z)

i want to get something like this: [x= , y= , z= ]
but the result: []

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answered 2015-03-16 03:32:08 -0500

nbruin gravatar image

Vectors with symbolic entries are not themselves "symbolic", so you can't put them in places where symbolic equations are expected:

sage: v2.cross_product(v3)==0
False

You can work around that, though:

sage: solve(v2.cross_product(v3).list() + [v1.dot_product(v3)==1440],x,y,z)
[[x == -324, y == -144, z == 216]]
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Asked: 2015-03-15 21:15:30 -0500

Seen: 66 times

Last updated: Mar 16 '15