document.write( "Question 582305: please help me with the following questions
\n" ); document.write( "1. Determine the value of the following expression without using a calculator?
\n" ); document.write( "tan210degrees x sin 240 degrees x cos 180 degrees divided by 405 degrees sin (-225degrees)
\n" ); document.write( "2. If tan 25degreees = a, determine in terms of a the value of:
\n" ); document.write( "tan205degrees - tan115degrees divided by tan245degrees + tan335degrees.
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Algebra.Com's Answer #372262 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
The trigonometric functions of angles in the second, third and fourth quadrants have the same absolute value as the trigonometric functions of a reference angle in the first quadrant. The reference angle is a reflection on one of the axes (x axis or y axis, or on the origin.
\n" ); document.write( "The trigonometric functions of \"0%5Eo\", \"30%5Eo\", \"45%5Eo\", \"60%5Eo\", and \"90%5Eo\", are all you need when they say \"without using a calculator.\"
\n" ); document.write( "1. \"210%5Eo=180%5Eo%2B30%5Eo\" so \"tan%28210%5Eo%29=tan%2830%5Eo%29=sqrt%283%29%2F3\"
\n" ); document.write( "\"240%5Eo=180%5Eo%2B60%5Eo\" so \"sin%28240%5Eo%29=-sin%2860%5Eo%29=-sqrt%283%29%2F2\"
\n" ); document.write( "\"cos%28180%5Eo%29=-1\"
\n" ); document.write( "I don't know what \"405%5Eo\" is doing, all by itself in your problem. I expected to see some trigonometric function of \"405%5Eo\", not just the angle measure. In any case,
\n" ); document.write( "\"405%5Eo=360%5Eo%2B45%5Eo\", so the trigonometric functions for \"405%5Eo\" are the same as for \"45%5Eo\". (They are co-terminal angles).
\n" ); document.write( "\"-225%5Eo%2B180%5Eo=-45%5Eo\", so \"sin%28-225%5Eo%29=-sin%28-45%5Eo%29=-%28-sin%2845%5Eo%29%29=sin%2845%5Eo%29=sqrt%282%29%2F2\"
\n" ); document.write( "2. If \"tan%2825%5Eo%29=a\", since \"65%5Eo%2B25%5Eo=90%5Eo\", \"tan%2865%5Eo%29=1%2Ftan%2825%5Eo%29=1%2Fa\".
\n" ); document.write( "From there you can find the tangents of angles that have \"65%5Eo\" or \"25%5Eo\" as reference angle.
\n" ); document.write( "\"205%5Eo=180%5Eo%2B25%5Eo\", so \"tan%28205%5Eo%29=tan%2825%5Eo%29=a\"
\n" ); document.write( "\"115%5Eo=180%5Eo-65%5Eo\", so \"tan%28115%5Eo%29=-tan%2865%5Eo%29=-1%2Fa\"
\n" ); document.write( "\"245%5Eo=180%5Eo%2B65%5Eo\", so \"tan%28245%5Eo%29=tan%2865%5Eo%29=1%2Fa\"
\n" ); document.write( "\"335%5Eo=360%5Eo-25%5Eo\", so \"tan%28335%5Eo%29=tan%28-25%5Eo%29=-tan%2825%5Eo%29=-a\"
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