Thread: Angle between two vectors

Im trying to find the angle between two vectors on Maple 13. I type in: "VectorAngle((3,7,7),(8,6,2))" and it gives me . This simplifies to .71 radians or about . The problem is the angle is supposed to be over 70 degrees from what I've worked out. Are my calculations wrong or did i type something in wrong in the calculator?

I'm not sure if this is important, but when i typed in my vectors I, instead of the inside parentheses in red above, used some strange symbols that looked like < and > but taller and skinnier, but i don't know how to type these i had just copy-pasted them from somewhere else. When i copy-paste them here, though, they show up as <>, but they don't look the same when i try to type them into Maple as <>. I just don't get this at all

Mathcad gave me the exact same result.
Check your vectors.

There are ambiguities in the inverse cosine function. Another answer in the range of 0 to 360 degrees is 360 - 40 = 320 degrees. Does that answer make sense?

Yeah-- is what you're saying, right? Either way, it's not the answer I'm looking for. The answer I want is about 70 degrees.

Originally Posted by Plato

Mathcad gave me the exact same result.
Check your vectors.

Mkay, thanks. I figured my calculations were probably what went wrong, but I wanted to ask here first. My vectors are right, and I'm fairly certain my 70 degrees is right, but i guess it's back to the drawing board. :P

Originally Posted by Chokfull

Yeah-- is what you're saying, right? Either way, it's not the answer I'm looking for. The answer I want is about 70 degrees.

You may well be looking for an angle of but with those two vectors your not going to find it.
Again, check the vectors. Did you copy them correctly?
Or could there be a different way of reading the problem?

Yeah, like i said, I'm going to crunch all my numbers again. I'll probably post again if I don't find any mistakes in my math, but I'll betcha money I am.