Metamath Proof Explorer


Definition df-tanh

Description: Define the hyperbolic tangent function (tanh). We define it this way for cmpt , which requires the form ( x e. A |-> B ) . (Contributed by David A. Wheeler, 10-May-2015)

Ref Expression
Assertion df-tanh tanh = x cosh -1 0 tan i x i

Detailed syntax breakdown

Step Hyp Ref Expression
0 ctanh class tanh
1 vx setvar x
2 ccosh class cosh
3 2 ccnv class cosh -1
4 cc class
5 cc0 class 0
6 5 csn class 0
7 4 6 cdif class 0
8 3 7 cima class cosh -1 0
9 ctan class tan
10 ci class i
11 cmul class ×
12 1 cv setvar x
13 10 12 11 co class i x
14 13 9 cfv class tan i x
15 cdiv class ÷
16 14 10 15 co class tan i x i
17 1 8 16 cmpt class x cosh -1 0 tan i x i
18 0 17 wceq wff tanh = x cosh -1 0 tan i x i