- #1
thomas49th
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- 0
This question has a few parts.
r = i + 2j + 3k
s = 2i - 2j - 5k
t = i - 3j - k
Evaluate:
a)(r.t)s - (s.t)r
b)(r x s) x t.
deduce that (r.t)s - (s.t)r = (r x s) x t
can you prove this relative true for any three vectors
a)(r.t)s - (s.t)r
(r.t)s
well I don't know what s is doing to inside the bracket. I don't think it's the cross product rule.
Anyhow
(r.t) means use dotty dot product
r.t = |r||t|cos(x)
problem uno. I don't know the angle between the vectors.
Am I just being stupid. I thought about possibly trying to get the angle from the cross product, or using some trig identity but I think that'll be a road to nowhere
Hint?
Thanks
Thomas
r = i + 2j + 3k
s = 2i - 2j - 5k
t = i - 3j - k
Evaluate:
a)(r.t)s - (s.t)r
b)(r x s) x t.
deduce that (r.t)s - (s.t)r = (r x s) x t
can you prove this relative true for any three vectors
a)(r.t)s - (s.t)r
(r.t)s
well I don't know what s is doing to inside the bracket. I don't think it's the cross product rule.
Anyhow
(r.t) means use dotty dot product
r.t = |r||t|cos(x)
problem uno. I don't know the angle between the vectors.
Am I just being stupid. I thought about possibly trying to get the angle from the cross product, or using some trig identity but I think that'll be a road to nowhere
Hint?
Thanks
Thomas