document.write( "Question 1103234: A sinusoidal function has a maximum value of -5, a minimum value of -29, and
\n" ); document.write( "consecutive minimum values when \"x=-pi%2F5\" and \"x=+4pi%2F15\".
\n" ); document.write( "Determine the phase shift
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Algebra.Com's Answer #717936 by greenestamps(13216)\"\" \"About 
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\n" ); document.write( "Note that \"sinusoidal\" can mean either a sine function or a cosine function. I will choose to use a sine function.

\n" ); document.write( "The general form for the equation of a sine function is

\n" ); document.write( "\"y+=+A%2Asin%28B%28x-C%29%29%2BD\"

\n" ); document.write( "We are asked to find the phase shift, which is C.

\n" ); document.write( "The function has consecutive minimum values at \"x=-pi%2F5\" and \"x=+4pi%2F15\". The difference between those two values is \"7pi%2F15\".
\n" ); document.write( "So the period is \"7pi%2F15\"; that means B is \"2pi%2F%287pi%2F15%29=30%2F7\".

\n" ); document.write( "Since the given points are minimum values of the sine function, we want the phase shift to be 3/4 of the period (because sin(x) has its minimum value 3/4 of the way through a period), minus \"-pi%2F5\":
\n" ); document.write( "\"C=%283%2F4%29%287pi%2F15%29%2B%28pi%2F5%29+=+7pi%2F20%2B4pi%2F20+=+11pi%2F20\"

\n" ); document.write( "The phase shift is 11pi/20.

\n" ); document.write( "The maximum and minimum values of the function are -5 and -29; in the formula, that makes A=12 and D=-17.

\n" ); document.write( "So the complete function is
\n" ); document.write( "\"12%2Asin%28%2830%2F7%29%28x%2B11pi%2F20%29%29-17\"

\n" ); document.write( "Here is a graph....

\n" ); document.write( "\"graph%28300%2C200%2C-pi%2Cpi%2C-35%2C5%2C12%2Asin%28%2830%2F7%29%28x%2B11pi%2F20%29%29-17%29\"

\n" ); document.write( "The two minimum points closest to x=0 and on either of x=0 are at \"x=-pi%2F5\" and \"x=+4pi%2F15\".
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