take the difference between now you see the difference here here here right not the same error so here you will you in the W update use what we labeled error here in the G update you use this error here so this is the error of G so when you update the function G you want to make these two closer together such that G becomes a better inverse right because you're dealing with an approximate inverse you still need to obtain that approximate inverse end and this here is how you learn it this algorithm now achieves what we wanted right