Description: Relationship between cosine and arccosine. (Contributed by Mario Carneiro, 2-Apr-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | acoscosb | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cosacos | |
|
2 | 1 | 3ad2ant1 | |
3 | fveqeq2 | |
|
4 | 2 3 | syl5ibcom | |
5 | acoscos | |
|
6 | 5 | 3adant1 | |
7 | fveqeq2 | |
|
8 | 6 7 | syl5ibcom | |
9 | 4 8 | impbid | |