document.write( "Question 1077833: sec(5π/3)*tan(5π/4)-cot(2π/3)*sin(-π/3)
\n" ); document.write( "Evaluate each expression and simplyfy.
\n" ); document.write( "Can someone please help me? Thanks.
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Algebra.Com's Answer #692364 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
1) If you know (or figure out, or look up)
\n" ); document.write( "the values of the main trigonometric functions
\n" ); document.write( "(cosine, sine, and tangent)
\n" ); document.write( "for \"pi%2F3\" and \"pi%2F4\" ,
\n" ); document.write( "you are 1/3 of the way to the answer.
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\n" ); document.write( "2) You need to know some trigonometric identities that are really definitions:
\n" ); document.write( "\"cot%28theta%29=1%2Ftan%28theta%29\" , and \"sec%28theta%29=1%2Fcos%28theta%29\" .
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\n" ); document.write( "3) You also need to understand the relation between
\n" ); document.write( "angles in other quadrants and
\n" ); document.write( "their symmetrical first quadrant reference angles.
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\n" ); document.write( "Foe example (and relevant to the problem)
\n" ); document.write( "the diagram shows you that
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\n" ); document.write( "There are diagrams, tables and charts that can help you.
\n" ); document.write( "Your textbook probably has then.
\n" ); document.write( "Your teacher probably handed out that kind of help.
\n" ); document.write( "You can find them online searching for \"trig identities.\"
\n" ); document.write( "Wikipedia has a nice diagram, and a table.
\n" ); document.write( "However, you can figure out the answers by yourself,
\n" ); document.write( "with the Pythagorean theorem.
\n" ); document.write( "For \"pi%2F3\" think of half of an equilateral triangle.
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\n" ); document.write( "The Pythagorean theorem lets you figure out
\n" ); document.write( "the length of the long leg as \"h=sqrt%283%29%2F2\" .
\n" ); document.write( "So, for the \"pi%2F3=60%5Eo\" , we have the trigonometric ratios
\n" ); document.write( "\"cos%28pi%2F3%29=1%2F2\" , \"sin%28pi%2F3%29=sqrt%283%29%2F2\" , and \"tan%28pi%2F6%29=%28sqrt%283%29%2F2%29%2F%281%2F2%29=sqrt%283%29\" .
\n" ); document.write( "For \"pi%2F4\" think of half of a square.
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