Theorem ifeq1da 4511

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 4499	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4488	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4488	. . . 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 1541  ifcif 4479

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2115  ax-9 2123  ax-ext 2708

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-tru 1544  df-ex 1781  df-sb 2068  df-clab 2715  df-cleq 2728  df-clel 2811  df-rab 3400  df-v 3442  df-un 3906  df-if 4480

This theorem is referenced by:  ifeq12da  4513  cantnflem1d  9597  cantnflem1  9598  dfac12lem1  10054  xrmaxeq  13094  xrmineq  13095  rexmul  13186  max0add  15233  sumeq2ii  15616  fsumser  15653  ramcl  16957  dmdprdsplitlem  19968  coe1pwmul  22221  scmatscmiddistr  22452  mulmarep1gsum1  22517  maducoeval2  22584  madugsum  22587  madurid  22588  ptcld  23557  ibllem  25721  itgvallem3  25743  iblposlem  25749  iblss2  25763  iblmulc2  25788  cnplimc  25844  limcco  25850  dvexp3  25938  dchrinvcl  27220  lgsval2lem  27274  lgsval4lem  27275  lgsneg  27288  lgsmod  27290  lgsdilem2  27300  rpvmasum2  27479  esplyind  33731  mrsubrn  35707  ftc1anclem6  37899  ftc1anclem8  37901  fsuppind  42833