document.write( "Question 1182153: Given the graph below, determine a sine function and cosine function that can be used to represent the graph. Show all your work. \r
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Algebra.Com's Answer #812151 by greenestamps(13206)\"\" \"About 
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\n" ); document.write( "(1) Sine function

\n" ); document.write( "\"a%2Asin%28b%28x-c%29%29%2Bd\"

\n" ); document.write( "d is the midline. From the graph, d=3

\n" ); document.write( "a is the amplitude -- positive difference between the midline and the maximum or minimum. From the graph, a=3

\n" ); document.write( "b determines the period; the period is 360/b. On the graph, one period, as measured between consecutive maxima, is 60 degrees. 360/b=60, so b=6.

\n" ); document.write( "c is the phase shift. For a sine graph, at 0 the function is at the midline and increasing. The graph shows this occurring at x=30 degrees, so the phase shift c is 30.

\n" ); document.write( "We have a=3; b=6; c=30; d=3. The function is

\n" ); document.write( "\"3sin%286%28x-30%29%29%2B3\"

\n" ); document.write( "A graph (with the angle in radians)....

\n" ); document.write( "\"graph%28400%2C400%2C-pi%2F6%2Cpi%2C-2%2C8%2C3sin%286%28x-pi%2F6%29%29%2B3%29\"

\n" ); document.write( "(2) Cosine function

\n" ); document.write( "\"a%2Acos%28b%28x-c%29%29%2Bd\"

\n" ); document.write( "Compared to the sine function, for the cosine function parameters a (amplitude), b (period), and d (midline) will be the same as for the sine function; the only parameter that is different is c (phase shift).

\n" ); document.write( "For a cosine function, at 0 the function is at a maximum. The graph shows the first maximum for a positive angle occurring at 45 degrees. So for the cosine function the phase shift c is 45 degrees.

\n" ); document.write( "\"3cos%286%28x-45%29%29%2B3\"

\n" ); document.write( "A graph (with the angle in radians)....

\n" ); document.write( "\"graph%28400%2C400%2C-pi%2F6%2Cpi%2C-2%2C8%2C3cos%286%28x-pi%2F4%29%29%2B3%29\"

\n" ); document.write( "The graphs of these sine and cosine functions are identical, and they are the same as the given graph.

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