How to hide featured image in Single Post pages?

there are man posts about this but solutions are not working for me..
I ll be appreciated for your help..
hier ist the code I m playing

<?php
							echo '<div class="thecontent">' . apply_filters('the_content', get_the_content()) . '</div>';

I ve tried this one but I dont know how can I replace the code >
echo preg_replace('/<img[^>]+\>/i', '', get_the_content(), 1);