document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=606159>Question 606159</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi, please help me with my homework. Our teacher wants us to draw the graph of the functions defined by the equation\r<BR>\n" );
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document.write( "y = -2cos[(pi/2) - 2x)]\r<BR>\n" );
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document.write( "but I don't know how to do this. All I know is that I have to use the formula y = a cos(bx - c) but I don't know how or why or even where the formula came from. Please explain the steps to me because I really don't understand this lesson. Thank you.\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #382038 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=382038\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Hi, please help me with my homework. Our teacher wants us to draw the graph of the functions defined by the equation <BR>\n" );
document.write( "y = -2cos[(pi/2) - 2x)]<BR>\n" );
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document.write( "Equation for cos function: y=Acos(Bx-C), A=amplitude, Period=2&#960;/B, Phase shift=C/B<BR>\n" );
document.write( "Rewrite given equation:<BR>\n" );
document.write( "-2cos(-2x+&#960;/2)<BR>\n" );
document.write( "Amplitude=2<BR>\n" );
document.write( "B=2<BR>\n" );
document.write( "Period=2&#960;/B=&#960;<BR>\n" );
document.write( "1/4 Period=&#960;/4<BR>\n" );
document.write( "C=&#960;/2<BR>\n" );
document.write( "Phase shift=C/B=(&#960;/2)/2=&#960;/4 (to the right)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Steps for graphing given cos function for one period.<BR>\n" );
document.write( "Start with basic cos function, cos(-2x) with amplitude=1 and no phase shift.<BR>\n" );
document.write( "Coordinates as follows:<BR>\n" );
document.write( "(0,1), (&#960;/4,0), (&#960;/2,-1), (3&#960;/4,0), (&#960;,1)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Shifting &#960;/4 to the right<BR>\n" );
document.write( "(&#960;/4,1), (&#960;/2,0), (3&#960;/4,-1), (&#960;,0), (5&#960;/4,1)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Increase amplitude to 2 and reflect curve around x-axis<BR>\n" );
document.write( "(&#960;/4,-2), (&#960;/2,0), (3&#960;/4,2), (&#960;,0), (5&#960;/4,-2)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "y-intercept:<BR>\n" );
document.write( "set x=0<BR>\n" );
document.write( "-2cos(-2x+&#960;/2)=-2cos(&#960;/2)=0<BR>\n" );
document.write( "y-intercept=0<BR>\n" );
document.write( ".. <BR>\n" );
document.write( "You now have the y-intercept and coordinates to graph given cos function.<BR>\n" );
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