Theorem ifeq1da 4537

Description: Conditional equality. (Contributed by Jeff Madsen, 2-Sep-2009.)

Hypothesis

Ref	Expression
ifeq1da.1	⊢ ((𝜑 ∧ 𝜓) → 𝐴 = 𝐵)

Assertion

Ref	Expression
ifeq1da	⊢ (𝜑 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))

Proof of Theorem ifeq1da

Step	Hyp	Ref	Expression
1		ifeq1da.1	. . 3 ⊢ ((𝜑 ∧ 𝜓) → 𝐴 = 𝐵)
2	1	ifeq1d 4525	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4514	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4514	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐵, 𝐶) = 𝐶)
5	3, 4	eqtr4d 2774	. . 3 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
6	5	adantl 481	. 2 ⊢ ((𝜑 ∧ ¬ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
7	2, 6	pm2.61dan 812	1 ⊢ (𝜑 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 395   = wceq 1540  ifcif 4505

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2708

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-tru 1543  df-ex 1780  df-sb 2066  df-clab 2715  df-cleq 2728  df-clel 2810  df-rab 3421  df-v 3466  df-un 3936  df-if 4506

This theorem is referenced by:  ifeq12da  4539  cantnflem1d  9707  cantnflem1  9708  dfac12lem1  10163  xrmaxeq  13200  xrmineq  13201  rexmul  13292  max0add  15334  sumeq2ii  15714  fsumser  15751  ramcl  17054  dmdprdsplitlem  20025  coe1pwmul  22221  scmatscmiddistr  22451  mulmarep1gsum1  22516  maducoeval2  22583  madugsum  22586  madurid  22587  ptcld  23556  ibllem  25722  itgvallem3  25744  iblposlem  25750  iblss2  25764  iblmulc2  25789  cnplimc  25845  limcco  25851  dvexp3  25939  dchrinvcl  27221  lgsval2lem  27275  lgsval4lem  27276  lgsneg  27289  lgsmod  27291  lgsdilem2  27301  rpvmasum2  27480  mrsubrn  35540  ftc1anclem6  37727  ftc1anclem8  37729  fsuppind  42580