document.write( "Question 147049: Find K so that the vectors [4,-3] and [k,-6] (a) point in the same direction
\n" ); document.write( "(b) are perpendicular
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Algebra.Com's Answer #107395 by Fombitz(32388)\"\" \"About 
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a)Point in the same direction means the vectors are scaled versions of each other.
\n" ); document.write( "In other words, the x components are in the same proportion as the y components.
\n" ); document.write( "\"4%2Fk=%28-3%29%2F%28-6%29\"
\n" ); document.write( "\"k=8\"
\n" ); document.write( "b)Perpendicular vectors have a dot product equal to zero.
\n" ); document.write( "A:[4,-3]
\n" ); document.write( "B:[k,-6]
\n" ); document.write( "\"A%2AB=4%2Ak%2B%28-3%29%28-6%29=0\"
\n" ); document.write( "\"4%2Ak%2B18=0\"
\n" ); document.write( "\"4%2Ak=-18\"
\n" ); document.write( "\"k=-18%2F4\"
\n" ); document.write( "\"k=-9%2F2\"\r
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\n" ); document.write( "Graphical check of the answer.
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