1. ## Vectors problem/check

Vectors d and e are such that |d| = 3 and |e| = 5 and the angle between them is 30 degrees. Determine |d - e|.

I set it up like this:

And did |d-e| = \sqrt{9+25-2(3)(5)(cos30)} = 8.02

However the answer in the book is 2.83. Can anyone tell me where I'm going wrong or if it's a typo? Thanks!

2. Originally Posted by IanCarney
Vectors d and e are such that |d| = 3 and |e| = 5 and the angle between them is 30 degrees. Determine |d - e|.
And did |d-e| = \sqrt{9+25-2(3)(5)(cos30)} = 8.02
However the answer in the book is 2.83. Can anyone tell me where I'm going wrong or if it's a typo? Thanks!
I cannot see how you got that.
From the given the correct answer is $\displaystyle \sqrt{8.019}$.

3. Originally Posted by Plato
I cannot see how you got that.
From the given the correct answer is $\displaystyle \sqrt{19}$.
So the textbook is wrong.
How did you get $\displaystyle \sqrt{19}$

4. That is a typo. See my correction.

5. Originally Posted by Plato
That is a typo. See my correction.
Ah, thanks!