document.write( "Question 876351: Where are the x-intercepts for f(x) = 4 cos(2x − π) from x = 0 to x = 2π?\r
\n" ); document.write( "\n" ); document.write( "I have no idea where to begin. On WolframAlpha, it says the x int's are npi/2 - pi/4, where n is an element of the integers. I do not know how they arrived at that answer. \r
\n" ); document.write( "\n" ); document.write( "I know the amplitude is 4, the period is pi, but when I solve bx - h = 0 I get pi/2, but not pi/2 - pi/4. How do they obtain this answer?\r
\n" ); document.write( "\n" ); document.write( "Many thanks for your help \n" ); document.write( "

Algebra.Com's Answer #528722 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"cos%28z%29=0\"$ when $\"z=%281%2F2%29pi\"$ and $\"z=%283%2F2%29pi\"$
\n" ); document.write( "So then,
\n" ); document.write( " $\"2x-pi=%281%2F2%29pi\"$ and $\"2x-pi=%283%2F2%29pi\"$
\n" ); document.write( " $\"2x=%283%2F2%29pi\"$ and $\"2x=%285%2F2%29pi\"$
\n" ); document.write( " $\"x=%283%2F4%29pi\"$ and $\"x=%285%2F4%29pi\"$
\n" ); document.write( "And since cosine is periodic in $\"2pi\"$
\n" ); document.write( " $\"x=%283%2F4%29pi+%2B-+2pi%2An\"$ and $\"x=%285%2F4%29pi+%2B-+2pi%2An\"$
\n" ); document.write( "You can combine those two together to get the Wolfram answer.\r
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