Nonelementary integral

Do you remember learning how to add and subtract in math class? Well, sometimes when we do math, we need to figure out how to add or subtract really complicated things, like really big fractions or weird letters instead of numbers. Sometimes, we even need to figure out how to do a kind of math called integration, which is like undoing multiplication.

Now, most of the time, when we do integration, we can use easy rules and formulas to figure out the answer. But sometimes, we get a kind of math problem that's too hard even for the easy rules and formulas. That's when we have to use something called a nonelementary integral.

A nonelementary integral is a kind of math problem that's so complicated, we don't have any easy rules or formulas that can solve it. It's like trying to solve a super hard puzzle, but not knowing the answer because there's no one way to solve it.

Scientists and mathematicians still work on finding ways to solve nonelementary integrals, but so far, we don't have a way to solve all of them. It's like trying to figure out how to solve every puzzle in the world - it's really hard!

So that's what a nonelementary integral is - a really hard kind of math puzzle that we don't have an easy way to solve yet. But some really smart people are working on it every day, so maybe someday we'll be able to solve them all!