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anonymous

  • one year ago

Use the formula v1 x v2 = absltvalue v1 x absltvalue v2 to find the cosine of the angle between the two vectors (-7,8) and (1,0).

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  1. misty1212
    • one year ago
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    hi!!

  2. misty1212
    • one year ago
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    you got the length of each of these?

  3. misty1212
    • one year ago
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    dot product should be easy since because of the \((1,0)\) it is just \(-7\)

  4. anonymous
    • one year ago
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    So Im just curious in the equation when it says multiply v1 by v2 does that mean you multiply the x and y values of (-7,8) and (1,0) together and than add the x and y values together?

  5. dumbcow
    • one year ago
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    ^^ yes \[v_1*v_2 = (x_1,y_1) * (x_2,y_2) = x_1 *x_2 + y_1*y_2\]

  6. anonymous
    • one year ago
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    so the equation would come out to be -7=7costheta. Which would then simplify down to -1=costheta. Then you solve for theta giving you 180 degrees?

  7. anonymous
    • one year ago
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    @dumbcow

  8. dumbcow
    • one year ago
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    equation is \[\cos \theta = \frac{v_1 *v_2}{|v_1| |v_2|}\] \[\cos \theta = \frac{-7}{\sqrt{113}}\] \[\theta \approx 131.2\]

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