# Thread: How do you do this problem?

1. ## How do you do this problem?

Please offer step by step solutions

There are three vectors. They are v= (3,-1,2), b= (4,2,-5) and n= (1,3,-7). Please prove that they form a closed triangle. What type of triangle is it?

Thanks!!!

2. ## Re: How do you do this problem?

Originally Posted by mortifiedpenguin1
Please offer step by step solutions
Sorry, this is not a homework service. You can ask for hints and ideas, but not complete solutions.

Originally Posted by mortifiedpenguin1
There are three vectors. They are v= (3,-1,2), b= (4,2,-5) and n= (1,3,-7). Please prove that they form a closed triangle.
Prove that for some combination of + and -, ± v ± b ± n = 0.

Originally Posted by mortifiedpenguin1
What type of triangle is it?
You can find out if the angle between two vectors is acute, right or obtuse by taking the dot product of the vectors. You have to be careful with orientation, though. For example, for the following vectors:

the dot product $\displaystyle \vec{x}\cdot\vec{y}$ is negative even though the angle is acute. That's because when the vectors are drawn having the same starting point, the angle between them is obtuse.

3. ## Re: How do you do this problem?

What does the fact that the scalar product of v and b =0 tell you

4. ## Re: How do you do this problem?

Originally Posted by biffboy
What does the fact that the scalar product of v and b =0 tell you
If the dot product of two vectors is zero then those vectors are perpendicular.