- #1

- 68

- 4

For example

-0.0288067i + -0.989524j + -0.141463k

0.169194i + -0.0644865j + -0.983471k

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- Thread starter Marioqwe
- Start date

- #1

- 68

- 4

For example

-0.0288067i + -0.989524j + -0.141463k

0.169194i + -0.0644865j + -0.983471k

- #2

- 998

- 15

... I am trying to find the angle between two unit vectors ...

The unit vectors [itex]\underline{i}[/itex],[itex]\underline{j}[/itex]and [itex]\underline{k}[/itex] all are at right angles to each other just like the x,y,and z co-ordinate axes.

Does your difficulty refer to the angle between two vectors which are not unit vectors?

- #3

- 68

- 4

- #4

- 68

- 4

Nevermind !

- #5

- 998

- 15

The above will always be greater than -1 and less than +1.

- #6

- 68

- 4

0.444119i + 0.666155j + 0.599163k

-0.0587215i + 0.732467j + 0.678265k

the dot product is 1.73928, and the magnitude of each vector is 1. How do you calculate the angle between them? :(

- #7

- 1,387

- 2

0.444119i + 0.666155j + 0.599163k

-0.0587215i + 0.732467j + 0.678265k

the dot product is 1.73928, and the magnitude of each vector is 1. How do you calculate the angle between them? :(

Are you sure? I get a dot product of 0.868249 for these vectors, and 0.198062 for the vectors in your first post.

- #8

HallsofIvy

Science Advisor

Homework Helper

- 41,847

- 969

(-0.0260793338585)+ (0.487936554385)+ (0.406391292195)= 0.8682485127215

just as Rasalhaque did.

Perhaps if you showed more detail on how you are doing the dot product we could see where your error is.

- #9

- 998

- 15

You must have a mistake in the calculations.

There is NO WAY that (v1 dot v2)/(magnitude of v1*magnitude of v2) is greater than 1 or less than -1.

- #10

- 998

- 15

I have a feeling that Marioque is enjoying seeing us calculating!!

- #11

- 998

- 15

I also got 0.8682484 for the dot product.

- #12

- 68

- 4

jaja! grzz. It was my mistake again :(. No more dumb questions. I'm really sorry.

- #13

- 998

- 15

My maxim is:

One may sometimes swallow some water but that is the way one learns to swim!

Enjoy your 'swimming' in PhysicsForums!

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