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Numerade Educator



Problem 19 Easy Difficulty

Find the angle between the vectors. (First find an exact expression and then approximate to the nearest degree.)

$ a = 4i - 3j + k , b = 2i - k $




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Video Transcript

Okay, so we're gonna use this formula to figure out what this angle is. So first we need a dot Be, that's going to be four times two plus negative. Three times zero plus one times one. Um so it's gonna end up being nine. Now, we need the magnitude of a or squared plus negative three squared plus one squared. And this ends up being right. 26. Then we got the magnitude of B got two squared, plus zero squared, plus negative one squared square to five. So then just manipulating this formula a little bit, we end up with this. And then we got nine over rad. Five times read 26. So co sign inverse of this whole thing will be equal to data.