Theorem ifeq1da 4555

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 4543	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4533	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4533	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐵, 𝐶) = 𝐶)
5	3, 4	eqtr4d 2770	. . 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 1534  ifcif 4524

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1964  ax-7 2004  ax-8 2101  ax-9 2109  ax-ext 2698

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 847  df-tru 1537  df-ex 1775  df-sb 2061  df-clab 2705  df-cleq 2719  df-clel 2805  df-rab 3428  df-v 3471  df-un 3949  df-if 4525

This theorem is referenced by:  ifeq12da  4557  cantnflem1d  9703  cantnflem1  9704  dfac12lem1  10158  xrmaxeq  13182  xrmineq  13183  rexmul  13274  max0add  15281  sumeq2ii  15663  fsumser  15700  ramcl  16989  dmdprdsplitlem  19985  coe1pwmul  22185  scmatscmiddistr  22397  mulmarep1gsum1  22462  maducoeval2  22529  madugsum  22532  madurid  22533  ptcld  23504  ibllem  25681  itgvallem3  25702  iblposlem  25708  iblss2  25722  iblmulc2  25747  cnplimc  25803  limcco  25809  dvexp3  25897  dchrinvcl  27173  lgsval2lem  27227  lgsval4lem  27228  lgsneg  27241  lgsmod  27243  lgsdilem2  27253  rpvmasum2  27432  mrsubrn  35059  ftc1anclem6  37106  ftc1anclem8  37108  fsuppind  41745