document.write( "Question 893601: Use the Maclaurin expansion of sin x to find the value of sin 45 correct to four decimal places \n" ); document.write( "
Algebra.Com's Answer #541588 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
The Maclaurin series expansion is,
\n" ); document.write( "\"f%28x%29=sum%28f%5E%28k%29%280%29%2A%28%28x-0%29%5Ek%2Fk%21%29%2Ck=0%2Cinfinity%29\"
\n" ); document.write( "where \"f%5Ek\" is the k-th derivative of the function.
\n" ); document.write( "In this case,
\n" ); document.write( "\"f%28x%29=sin%28x%29\"
\n" ); document.write( "\"f%5E%281%29%28x%29=cos%28x%29\"
\n" ); document.write( "\"f%5E%282%29%28x%29=-sin%28x%29\"
\n" ); document.write( "\"f%5E%283%29%28x%29=-cos%28x%29\"
\n" ); document.write( "\"f%5E%284%29%28x%29=sin%28x%29\"
\n" ); document.write( "\"f%5E%285%29%28x%29=cos%28x%29\"
\n" ); document.write( "\"f%5E%286%29%28x%29=-sin%28x%29\"
\n" ); document.write( "Then take the value of each at \"x=0\"
\n" ); document.write( "\"f%280%29=sin%280%29=0\"
\n" ); document.write( "\"f%5E%281%29%280%29=cos%280%29=1\"
\n" ); document.write( "\"f%5E%282%29%280%29=-sin%280%29=0\"
\n" ); document.write( "\"f%5E%283%29%280%29=-cos%280%29=-1\"
\n" ); document.write( "\"f%5E%284%29%280%29=sin%280%29=0\"
\n" ); document.write( "\"f%5E%285%29%280%29=cos%280%29=1\"
\n" ); document.write( "\"f%5E%286%29%280%29=-sin%280%29=0\"
\n" ); document.write( "Putting it all together,
\n" ); document.write( "
\n" ); document.write( "You begin to see the pattern,
\n" ); document.write( "\"sin%28x%29=x-%28x%29%5E3%2F3%21%2B%28x%29%5E5%2F5%21-%28x%29%5E7%2F7%21\"
\n" ); document.write( "So find the value of 45 degrees in radians,
\n" ); document.write( "\"45%28%282%2Api%29%2F360%29=0.785398\"
\n" ); document.write( "And substitute,
\n" ); document.write( "
\n" ); document.write( "\"sin%280.785398%29=0.707106\"
\n" ); document.write( "I think that's pretty good compared to \"sqrt%282%29%2F2=0.707107\"
\n" ); document.write( "\"sin%280.785398%29=0.7071\"
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