Multiplying.
No. Trial and error is the most inefficient way for factoring.
An inverse, without any qualification, is taken to be the multiplicative inverse. is The inverse of a number, x (x not 0), is 1 divided by x. Any number multiplied by its inverse must be equal to 1. There is also an additive inverse. For any number y, the additive inverse is -y. And the sum of the two must always be 0.
The inverse if cosine 0.55 is 0.55
Infinity
Yes