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Math Help - Vectors again

  1. #1
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    Vectors again

    v=-3i+j, w=4i-2j

    Find:

    1) 4v-3w does this equal -24i-2j

    2) ||V+W|| does this equal [tex] \sqrt{i^2-j^2} [ /math] I have an error if I take out the space between [ / that I do not know how to fix.

    3) How can I find the angle between v and w?
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  2. #2
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    Quote Originally Posted by IDontunderstand View Post
    v=-3i+j, w=4i-2j

    Find:

    1) 4v-3w does this equal -24i-2j

    yes

    2) ||V+W|| does this equal [tex] \sqrt{i^2-j^2} [ /math] I have an error if I take out the space between [ / that I do not know how to fix.

    |v+w| = |i - j| = \sqrt{1^2 + (-1)^2} = \sqrt{2}

    3) How can I find the angle between v and w?

    v \cdot w = |v| |w| \cos{\theta}
    btw, [tex] tags don't work ... use [tex] tags
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  3. #3
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    I figured it out thanks
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