Theorem ifeq1da 4499

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 4487	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4476	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4476	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐵, 𝐶) = 𝐶)
5	3, 4	eqtr4d 2775	. . 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 813	1 ⊢ (𝜑 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 395   = wceq 1542  ifcif 4467

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-ext 2709

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-tru 1545  df-ex 1782  df-sb 2069  df-clab 2716  df-cleq 2729  df-clel 2812  df-rab 3391  df-v 3432  df-un 3895  df-if 4468

This theorem is referenced by:  ifeq12da  4501  cantnflem1d  9603  cantnflem1  9604  dfac12lem1  10060  xrmaxeq  13125  xrmineq  13126  rexmul  13217  max0add  15266  sumeq2ii  15649  fsumser  15686  ramcl  16994  dmdprdsplitlem  20008  coe1pwmul  22257  scmatscmiddistr  22486  mulmarep1gsum1  22551  maducoeval2  22618  madugsum  22621  madurid  22622  ptcld  23591  ibllem  25744  itgvallem3  25766  iblposlem  25772  iblss2  25786  iblmulc2  25811  cnplimc  25867  limcco  25873  dvexp3  25958  dchrinvcl  27233  lgsval2lem  27287  lgsval4lem  27288  lgsneg  27301  lgsmod  27303  lgsdilem2  27313  rpvmasum2  27492  esplyind  33737  mrsubrn  35714  ftc1anclem6  38036  ftc1anclem8  38038  fsuppind  43040