Description: Lemma for ang180 : Reduce the statement to two variables. (Contributed by Mario Carneiro, 23-Sep-2014)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ang.1 | |
|
Assertion | ang180lem5 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ang.1 | |
|
2 | simp1l | |
|
3 | 1cnd | |
|
4 | simp2l | |
|
5 | simp1r | |
|
6 | 4 2 5 | divcld | |
7 | 2 3 6 | subdid | |
8 | 2 | mulridd | |
9 | 4 2 5 | divcan2d | |
10 | 8 9 | oveq12d | |
11 | 7 10 | eqtrd | |
12 | 11 8 | oveq12d | |
13 | 3 6 | subcld | |
14 | simp3 | |
|
15 | 14 | necomd | |
16 | 4 2 5 15 | divne1d | |
17 | 16 | necomd | |
18 | 3 6 17 | subne0d | |
19 | ax-1ne0 | |
|
20 | 19 | a1i | |
21 | 1 | angcan | |
22 | 13 18 3 20 2 5 21 | syl222anc | |
23 | 12 22 | eqtr3d | |
24 | 2 6 3 | subdid | |
25 | 9 8 | oveq12d | |
26 | 24 25 | eqtrd | |
27 | 9 26 | oveq12d | |
28 | simp2r | |
|
29 | 4 2 28 5 | divne0d | |
30 | 6 3 | subcld | |
31 | 6 3 16 | subne0d | |
32 | 1 | angcan | |
33 | 6 29 30 31 2 5 32 | syl222anc | |
34 | 27 33 | eqtr3d | |
35 | 23 34 | oveq12d | |
36 | 8 9 | oveq12d | |
37 | 1 | angcan | |
38 | 3 20 6 29 2 5 37 | syl222anc | |
39 | 36 38 | eqtr3d | |
40 | 35 39 | oveq12d | |
41 | 1 | ang180lem4 | |
42 | 6 29 16 41 | syl3anc | |
43 | 40 42 | eqeltrd | |