Theorem ifeq1da 4455

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 4443	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4434	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4434	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐵, 𝐶) = 𝐶)
5	3, 4	eqtr4d 2836	. . 3 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
6	5	adantl 485	. 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 399   = wceq 1538  ifcif 4425

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 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-12 2175  ax-ext 2770

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-ex 1782  df-nf 1786  df-sb 2070  df-clab 2777  df-cleq 2791  df-clel 2870  df-rab 3115  df-v 3443  df-un 3886  df-if 4426

This theorem is referenced by:  ifeq12da  4457  cantnflem1d  9135  cantnflem1  9136  dfac12lem1  9554  xrmaxeq  12560  xrmineq  12561  rexmul  12652  max0add  14662  sumeq2ii  15042  fsumser  15079  ramcl  16355  dmdprdsplitlem  19152  coe1pwmul  20908  scmatscmiddistr  21113  mulmarep1gsum1  21178  maducoeval2  21245  madugsum  21248  madurid  21249  ptcld  22218  ibllem  24368  itgvallem3  24389  iblposlem  24395  iblss2  24409  iblmulc2  24434  cnplimc  24490  limcco  24496  dvexp3  24581  dchrinvcl  25837  lgsval2lem  25891  lgsval4lem  25892  lgsneg  25905  lgsmod  25907  lgsdilem2  25917  rpvmasum2  26096  mrsubrn  32873  ftc1anclem6  35135  ftc1anclem8  35137  fsuppind  39456