document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1042541>Question 1042541</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In Crescent Moon Bay in July, high tide is at 3:00 pm. The water level is 6 feet at high tide and 2 feet at low tide. Assuming the next high tide is exactly 12 hours later and the height of the water can be modeled by a cosine curve, find an equation for Crescent Moon Bay's water level in July as a function of time (t).\r<BR>\n" );
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document.write( "need to show work </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #657509 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=657509\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The high tide is 2 feet above a level of 4 ft<BR>\n" );
document.write( "and the low tide is 2 ft below that level of 4 ft<BR>\n" );
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document.write( "That tells me the amplitude must be <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2+ ALIGN=MIDDLE  ALT=\"+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and I have to add a constant of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4+ ALIGN=MIDDLE  ALT=\"+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  to the cosine<BR>\n" );
document.write( "function<BR>\n" );
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document.write( "If the function is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+f%28x%29+ ALIGN=MIDDLE  ALT=\"+f%28x%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then I want <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+0+ ALIGN=MIDDLE  ALT=\"+x+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+12+ ALIGN=MIDDLE  ALT=\"+x+=+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" > to equal 1 period ( 12 hrs )<BR>\n" );
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document.write( "So far the function looks like:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+f%28x%29+=+2%2Acos%28+k%2Ax+%29+%2B+4+ ALIGN=MIDDLE  ALT=\"+f%28x%29+=+2%2Acos%28+k%2Ax+%29+%2B+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+f%2812%29+=+2%2Acos%28+k%2A12+%29+%2B+4+ ALIGN=MIDDLE  ALT=\"+f%2812%29+=+2%2Acos%28+k%2A12+%29+%2B+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+k%2Ax+=+2%2Api+ ALIGN=MIDDLE  ALT=\"+k%2Ax+=+2%2Api+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ( 1 period of the cosine )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+k%2A12+=+2%2Api+ ALIGN=MIDDLE  ALT=\"+k%2A12+=+2%2Api+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+k+=+pi%2F6+ ALIGN=MIDDLE  ALT=\"+k+=+pi%2F6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Now I have:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+f%28x%29+=+2%2Acos%28+%28pi%2F6%29%2Ax+%29++%2B+4+ ALIGN=MIDDLE  ALT=\"+f%28x%29+=+2%2Acos%28+%28pi%2F6%29%2Ax+%29++%2B+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "Here's a plot of 1 period of the function<BR>\n" );
document.write( "from <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+0+ ALIGN=MIDDLE  ALT=\"+x+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+12+ ALIGN=MIDDLE  ALT=\"+x+=+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+600%2C+300%2C+-1%2C+13%2C+-1%2C+6%2C+2%2Acos%28+%28+pi%2F6%29%2Ax+%29+%2B+4+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+600%2C+300%2C+-1%2C+13%2C+-1%2C+6%2C+2%2Acos%28+%28+pi%2F6%29%2Ax+%29+%2B+4+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );