discovered
Wrong, it was invented.
Things that preexisted our awareness of them are discovered.
Things that did not exist until we created them are invented.
It was invented in1859.
Sigma notation was invented, not discovered.Sigma notation was invented, not discovered.Sigma notation was invented, not discovered.Sigma notation was invented, not discovered.
Discovered
It was not discovered but invented.
They were not discovered, they were invented.
discovered
It was not discovered but invented.
The first solar battery was invented in 1954.
It was not discovered, it was invented.
It was not discovered it was invented.
It was invented, not discovered.
it is discovered