vector a = (2,5) and vector b = (-1,t)
solve for t when the vectors have a 45 degree angle between them
any help would be appreciated.
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If I remember correctly you can use the dot product
hm, yeah thats what I figured. I can't figure out how to solve from there on.
Where are you having trouble? It just ends up becoming a quadratic after you square both sides.
This one does factor but it might be easier to use the quadratic formula
I tried that but Ididn't get the correct answer. the answer is t=7/3
Yes, that is the positive answer you get when you solve the quadratic.
Last edited by Quacky; Jan 11th 2011 at 09:39 AM.
Reason: Clarified formula usage
ah okay, i'll give it another go
I've editted the post. Where was your mistake? I assume it was probably just a sign error or something.
Last edited by Quacky; Jan 11th 2011 at 09:38 AM.
Originally Posted by colorado I tried that but Ididn't get the correct answer. the answer is t=7/3 Please show your working rather than just giving an answer. Then it is easier to diagnose what help you actually need.
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