Theorem ifeq1da 4513

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 4501	. 2 ⊢ ((𝜑 ∧ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
3		iffalse 4490	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = 𝐶)
4		iffalse 4490	. . . 4 ⊢ (¬ 𝜓 → if(𝜓, 𝐵, 𝐶) = 𝐶)
5	3, 4	eqtr4d 2798	. . 3 ⊢ (¬ 𝜓 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
6	5	adantl 487	. 2 ⊢ ((𝜑 ∧ ¬ 𝜓) → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))
7	2, 6	pm2.61dan 825	1 ⊢ (𝜑 → if(𝜓, 𝐴, 𝐶) = if(𝜓, 𝐵, 𝐶))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 401   = wceq 1569  ifcif 4481

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-ext 2732

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-tru 1572  df-ex 1812  df-sb 2099  df-clab 2739  df-cleq 2752  df-clel 2835  df-rab 3413  df-v 3452  df-un 4150  df-if 4482

This theorem is used by:  ifeq12da  4515  cantnflem1d  9696  cantnflem1  9697  dfac12lem1  10229  xrmaxeq  13316  xrmineq  13317  rexmul  13408  max0add  15486  sumeq2ii  15869  fsumser  15905  ramcl  17216  dmdprdsplitlem  20262  coe1pwmul  22607  scmatscmiddistr  22832  mulmarep1gsum1  22897  maducoeval2  22964  madugsum  22967  madurid  22968  ptcld  23941  ibllem  26094  itgvallem3  26115  iblposlem  26121  iblss2  26135  iblmulc2  26160  cnplimc  26216  limcco  26222  dvexp3  26307  dchrinvcl  27589  lgsval2lem  27643  lgsval4lem  27644  lgsneg  27657  lgsmod  27659  lgsdilem2  27669  rpvmasum2  27848  esplyind  34257  mrsubrn  36396  ftc1anclem6  38753  ftc1anclem8  38755  fsuppind  43755