Description: Absolute value distributes over multiplication. Proposition 10-3.7(f) of Gleason p. 133. (Contributed by NM, 1-Oct-1999)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | absvalsqi.1 | |- A e. CC |
|
| abssub.2 | |- B e. CC |
||
| Assertion | absmuli | |- ( abs ` ( A x. B ) ) = ( ( abs ` A ) x. ( abs ` B ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | absvalsqi.1 | |- A e. CC |
|
| 2 | abssub.2 | |- B e. CC |
|
| 3 | absmul | |- ( ( A e. CC /\ B e. CC ) -> ( abs ` ( A x. B ) ) = ( ( abs ` A ) x. ( abs ` B ) ) ) |
|
| 4 | 1 2 3 | mp2an | |- ( abs ` ( A x. B ) ) = ( ( abs ` A ) x. ( abs ` B ) ) |