document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1173623>Question 1173623</A>: <I><SPAN STYLE=\"word-break: break-all;\"> u =−6i − 2j<BR>\n" );
document.write( "v= −9i + 4j\r<BR>\n" );
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document.write( "Find the degree measure of the angle 𝜃 between the vectors. (Round your answer to two decimal places.)\r<BR>\n" );
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document.write( "𝜃 =_____° </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #798904 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52790)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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/cgi-bin/show-face.mpl?user=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=798904\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "You just got two solutions from Edwin, &nbsp;and you, &nbsp;probably, &nbsp;have a question, &nbsp;which approach/method to prefer.\r<BR>\n" );
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document.write( "Of these two approaches, &nbsp;the method using cosine is &nbsp;ROBUST &nbsp;and works &nbsp;ALWAYS, &nbsp;and &nbsp;ALWAYS &nbsp;produces correct results.\r<BR>\n" );
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document.write( "The Edwin's formulas with tan and arctan have a huge underwater stone.\r<BR>\n" );
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document.write( "In this form, as they presented, &nbsp;they work and they produce a correct answer for an &nbsp;ACUTE &nbsp;angle, &nbsp;ONLY.\r<BR>\n" );
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document.write( "For an &nbsp;OBTUSE &nbsp;angle they do not work.\r<BR>\n" );
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document.write( "AGAIN: &nbsp;&nbsp;the method using cosine and scalar products, &nbsp;is &nbsp;ROBUST &nbsp;and &nbsp;STANDARD &nbsp;method for such problems.\r<BR>\n" );
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document.write( "For them, &nbsp;use it and &nbsp;ONLY &nbsp;it . . . \r<BR>\n" );
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document.write( "---------------------\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/Vectors/Introduction-to-dot-product.lesson>Introduction to dot-product</A>\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/Vectors/Formula-for-Dot-product-of-vectors-in-a-plane-via-the-vectors-components.lesson>Formula for Dot-product of vectors in a plane via the vectors components</A>\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/Vectors/Dot-product-of-vectors-in-a-plane-and-the-angle-between-two-vectors.lesson>Dot-product of vectors in a coordinate plane and the angle between two vectors</A> (*)\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/Vectors/Solved-problems-on-Dot-product-of-vectors-and-the-angle-between-two-vectors.lesson>Solved problems on Dot-product of vectors and the angle between two vectors</A> \r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/word/geometry/HOW-TO-find-dot-product-of-two-vectors-in-a-plane.lesson>HOW TO find dot-product of two vectors in a plane</A>\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/word/geometry/HOW-TO-find-scalar-product-of-two-vectors-in-a-coordinate-plane.lesson>HOW TO find scalar product of two vectors in a coordinate plane</A>\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=http://www.algebra.com/algebra/homework/word/geometry/HOW-TO-find-the-angle-between-two-vectors-in-a-coordinate-plane.lesson>HOW TO find the angle between two vectors in a coordinate plane</A>\r<BR>\n" );
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document.write( "Of these lessons, the key is the lesson marked (*) in the list.\r<BR>\n" );
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document.write( "It is the most relevant lesson to your problem.\r<BR>\n" );
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document.write( "Other lessons illustrate how everything work.\r<BR>\n" );
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document.write( "Also, &nbsp;you have this free of charge online textbook in ALGEBRA-II in this site\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;- <A  rel=nofollow HREF=https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-II - YOUR ONLINE TEXTBOOK</A>.\r<BR>\n" );
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document.write( "The referred lessons are the part of this online textbook under the topic<BR>\n" );
document.write( "\"<U>Dot-product for vectors in a coordinate plane</U>\".\r<BR>\n" );
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document.write( "Save the link to this textbook together with its description\r<BR>\n" );
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document.write( "Free of charge online textbook in ALGEBRA-II<BR>\n" );
document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r<BR>\n" );
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document.write( "into your archive and use when it is needed.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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