Erase the top part and it becomes iloveyou.

Extended data:

The mathematical formula of I love you comes from a MV by Korean singer K.will, named "I Need You". The girl wrote a mathematical formula "128 radical e980" on the blackboard for the hero to answer, but the hero couldn't figure it out after thinking hard, so the girl picked up a brush and erased the upper part of the formula, which became English I Love You.

The formula "I love you" appears in "I need you" MV 1 minute 50 seconds, and it is also used in the romantic movie "Uncle" and appears in 1 hour 1 second.

References:

Baidu Encyclopedia entry-"I need you"