document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=582471>Question 582471</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Is my answer correct? <BR>\n" );
document.write( "Suppose u, v and w are vectors in 3-space. Which are/is defined?\r<BR>\n" );
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document.write( "A) (v.w) . u<BR>\n" );
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document.write( "B) (w x u) x v<BR>\n" );
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document.write( "My answer is only A is defined  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #372071 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=372071\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A)\r<BR>\n" );
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document.write( "This is <font color=\"red\">NOT defined</font>. The expression v.w results to be a scalar. Recall that the dot product a.b is only defined if BOTH a and b are vectors (of the same dimension). But since v.w is a scalar, the dot product isn't defined for z.u where z = v.w (because z is a scalar)\r<BR>\n" );
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document.write( "B)\r<BR>\n" );
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document.write( "This is <font color=\"red\">defined</font>. Both w and u are vectors in R3. So w x u is a vector in R3. If we let z = w x u, then (w x u) x v becomes z x v. So z is a vector in R3. The quantity v is a vector in R3. \r<BR>\n" );
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document.write( "This means that z x v is a vector in R3\r<BR>\n" );
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document.write( "Note: keep in mind that the cross product between vectors u and v is only defined if both u and v are vectors in R3 (3-space)\r<BR>\n" );
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