The use of "pi" here doesn't make sense. It looks like you may be treating it as if it means "of" which it doesn't. "pi" says "group the stuff to the right first, then use that group to modify what's on the left.
The use of "pi" here doesn't make sense. It looks like you may be treating it as if it means "of" which it doesn't. "pi" says "group the stuff to the right first, then use that group to modify what's on the left.