using iframe in php

The following code works in a Wordpress page. The php variable $start_day will echo 'Aug-09-2015', the same date used in the iframe.
How do I get the iframe to work using the variable  $start_day?

 // set the default timezone to use. Available since PHP 5.1
$s = date("Y/m/d");
$time = strtotime($s);
$start = strtotime('last sunday, 12pm', $time);
$end = strtotime('next sunday, 11:59am', $time);
$format = 'M\-d\-Y';
$start_day = date($format, $start);
$end_day = date($format, $end);
header('Content-Type: text/plain');
echo "Input: $s\nOutput: $start_day - $end_day";

<iframe id="pdf" src="" frameborder="0" style="border:none; width:100%; height:900px; background: #d1d1d1;" scrolling="yes"></iframe>
<div style="height: 20px;"></div>
Gary SamuelsPlant ManagerAsked:
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Please specify the error if possible

<iframe id='pdf' src='<?php echo $start_day; ?>.pdf&embedded=true' frameborder='0' style='border:none; width:100%; height:900px; background: #d1d1d1;' scrolling='yes'></iframe>
<div style='height: 20px;'></div>

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Julian HansenCommented:
Your query is not clear.

The PHP script simply sends a date to the requesting agent.

The iframe code seems to be displaying a PDF - how are you wanting to mix these two?
Gary SamuelsPlant ManagerAuthor Commented:
That worked, thanks
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