document.write( "Question 252605: The height of the ocean at the dock is modeled by the function, h= 3sin(pi*t/4) +5 where h is measured in feet and t is the time in hours. If t=0 refers to 12:00 a.m., what is the height of the ocean at 10:00 a.m.?\r
\n" ); document.write( "\n" ); document.write( "find the exact value of the vertical asymptotes for 0<=x<=pi for the function y=cot(3x)\r
\n" ); document.write( "\n" ); document.write( "if sin(x)= -3/5 with x in the quadrant 4, find the sec(x)\r
\n" ); document.write( "\n" ); document.write( "Thanks so much!!
\n" ); document.write( "

Algebra.Com's Answer #184615 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
I'll do the first two to get you going.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "# 1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since \"t=0 refers to 12:00 a.m\", this means that \"t=10\" refers to 10:00 a.m. (just add 10 hours to 0)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%28pi%2At%2F4%29%2B5\" Start with the given equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%28pi%2A10%2F4%29%2B5\" Plug in \"t=10\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%28pi%2A5%2F2%29%2B5\" Reduce.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%285pi%2F2%29%2B5\" Rearrange the terms\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%285pi%2F2-2pi%29%2B5\" Subtract \"2pi\" from the argument (this is valid because you'll end up on a coterminal angle).\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2Asin%28pi%2F2%29%2B5\" Combine like terms.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2A1%2B5\" Use the unit circle to evaluate the sine of \"pi%2F2\" to get 1.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=3%2B5\" Multiply\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"h=8\" Add\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the height of the ocean at 10:00 a.m. is 8 feet. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "=================================================================\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "# 2\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Remember that \"cot%28x%29=1%2Ftan%28x%29\" and \"tan%28x%29=sin%28x%29%2Fcos%28x%29\". So this means that \"cot%283x%29=1%2Ftan%283x%29=1%2F%28sin%283x%29%2Fcos%283x%29%29=cos%283x%29%2Fsin%283x%29\" or in short, \"cot%283x%29=cos%283x%29%2Fsin%283x%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "To find the vertical asymptotes of \"cot%283x%29=cos%283x%29%2Fsin%283x%29\", we'll set the denominator equal to zero and solve for 'x' (since division by zero is undefined).\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"sin%283x%29=0\" Set the denominator equal to zero.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3x=arcsin%280%29\" Take the arcsine of both sides.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=0%2B2pi%2An\" or \"x=pi%2B2pi%2An\" Evaluate the arcsine of 0 to get \"x=0\" or \"x=pi\". Don't forget to add on multiples of \"2pi\" to each solution.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%280%2B2pi%2An%29%2F3\" or \"x=%28pi%2B2pi%2An%29%2F3\" Divide both sides by 3 to isolate 'x' in each case. \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "As a shortcut, you can condense the solution to \"x=%281%2F3%29pi%2An\" where 'n' is an integer. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So if \"x=%281%2F3%29pi%2An\", where 'n' is an integer, then \"sin%283x%29=0\". \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "But since \"0%3C=x%3C=pi\", this means that we're only going to look at the solutions \"x=0\" (for n=0), \"x=pi%2F3\" (where n=1), \"x=2pi%2F3\" (when n=2), and \"x=pi\" (when x=3). Note: any other solution is outside the interval \"0%3C=x%3C=pi\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the four vertical asymptotes of \"cot%283x%29\" are \"x=0\", \"x=pi%2F3\", \"x=2pi%2F3\", and \"x=pi\"
\n" ); document.write( "
\n" );