Description: The product of two nonnegative numbers is nonnegative. (Contributed by NM, 30-Jul-1999)
Ref | Expression | ||
---|---|---|---|
Hypotheses | lt2.1 | ||
lt2.2 | |||
Assertion | mulge0i |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | lt2.1 | ||
2 | lt2.2 | ||
3 | mulge0 | ||
4 | 3 | an4s | |
5 | 1 2 4 | mpanl12 |