Description: Absolute value of a real number. (Contributed by NM, 17-Mar-2005)
Ref | Expression | ||
---|---|---|---|
Assertion | absre | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | recn | |
|
2 | absval | |
|
3 | 1 2 | syl | |
4 | 1 | sqvald | |
5 | cjre | |
|
6 | 5 | oveq2d | |
7 | 4 6 | eqtr4d | |
8 | 7 | fveq2d | |
9 | 3 8 | eqtr4d | |