phpExcel - Excel found unreadable content when use formula? -

i wrote code when open excel file had error "excel found unreadable content". here code

$i=8 $objphpexcel->getactivesheet()->setcellvalue('f'.$i,'=d.$i*e.$i'); $i++; 

where mistake? thank you!

your mistake single quotes ('), means php won't interpolate variables inside string, , you're not breaking out of string concatenation.

use double quotes (") without trying concatenate:

"=d{$i}*e{$i}" 

or concatenate:

'=d'.$i.'*e.'$i