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Theorem pythagtriplem17 12900
Description: Lemma for pythagtrip 12903. Show the relationship between  M,  N, and  C. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
Hypotheses
Ref Expression
pythagtriplem15.1  |-  M  =  ( ( ( sqr `  ( C  +  B
) )  +  ( sqr `  ( C  -  B ) ) )  /  2 )
pythagtriplem15.2  |-  N  =  ( ( ( sqr `  ( C  +  B
) )  -  ( sqr `  ( C  -  B ) ) )  /  2 )
Assertion
Ref Expression
pythagtriplem17  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  C  =  ( ( M ^ 2 )  +  ( N ^ 2 ) ) )

Proof of Theorem pythagtriplem17
StepHypRef Expression
1 pythagtriplem15.1 . . . . 5  |-  M  =  ( ( ( sqr `  ( C  +  B
) )  +  ( sqr `  ( C  -  B ) ) )  /  2 )
21pythagtriplem12 12895 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  ( M ^ 2 )  =  ( ( C  +  A )  /  2
) )
3 pythagtriplem15.2 . . . . 5  |-  N  =  ( ( ( sqr `  ( C  +  B
) )  -  ( sqr `  ( C  -  B ) ) )  /  2 )
43pythagtriplem14 12897 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  ( N ^ 2 )  =  ( ( C  -  A )  /  2
) )
52, 4oveq12d 5892 . . 3  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( M ^ 2 )  +  ( N ^ 2 ) )  =  ( ( ( C  +  A )  /  2 )  +  ( ( C  -  A )  /  2
) ) )
6 nncn 9770 . . . . . . 7  |-  ( C  e.  NN  ->  C  e.  CC )
763ad2ant3 978 . . . . . 6  |-  ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  ->  C  e.  CC )
873ad2ant1 976 . . . . 5  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  C  e.  CC )
9 nncn 9770 . . . . . . 7  |-  ( A  e.  NN  ->  A  e.  CC )
1093ad2ant1 976 . . . . . 6  |-  ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  ->  A  e.  CC )
11103ad2ant1 976 . . . . 5  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  A  e.  CC )
128, 11addcld 8870 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  ( C  +  A )  e.  CC )
138, 11subcld 9173 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  ( C  -  A )  e.  CC )
14 2cn 9832 . . . . . 6  |-  2  e.  CC
15 2ne0 9845 . . . . . 6  |-  2  =/=  0
1614, 15pm3.2i 441 . . . . 5  |-  ( 2  e.  CC  /\  2  =/=  0 )
17 divdir 9463 . . . . 5  |-  ( ( ( C  +  A
)  e.  CC  /\  ( C  -  A
)  e.  CC  /\  ( 2  e.  CC  /\  2  =/=  0 ) )  ->  ( (
( C  +  A
)  +  ( C  -  A ) )  /  2 )  =  ( ( ( C  +  A )  / 
2 )  +  ( ( C  -  A
)  /  2 ) ) )
1816, 17mp3an3 1266 . . . 4  |-  ( ( ( C  +  A
)  e.  CC  /\  ( C  -  A
)  e.  CC )  ->  ( ( ( C  +  A )  +  ( C  -  A ) )  / 
2 )  =  ( ( ( C  +  A )  /  2
)  +  ( ( C  -  A )  /  2 ) ) )
1912, 13, 18syl2anc 642 . . 3  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( ( C  +  A )  +  ( C  -  A ) )  /  2 )  =  ( ( ( C  +  A )  /  2 )  +  ( ( C  -  A )  /  2
) ) )
205, 19eqtr4d 2331 . 2  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( M ^ 2 )  +  ( N ^ 2 ) )  =  ( ( ( C  +  A )  +  ( C  -  A ) )  / 
2 ) )
218, 11, 8ppncand 9213 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( C  +  A
)  +  ( C  -  A ) )  =  ( C  +  C ) )
2282timesd 9970 . . . 4  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
2  x.  C )  =  ( C  +  C ) )
2321, 22eqtr4d 2331 . . 3  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( C  +  A
)  +  ( C  -  A ) )  =  ( 2  x.  C ) )
2423oveq1d 5889 . 2  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( ( C  +  A )  +  ( C  -  A ) )  /  2 )  =  ( ( 2  x.  C )  / 
2 ) )
25 divcan3 9464 . . . 4  |-  ( ( C  e.  CC  /\  2  e.  CC  /\  2  =/=  0 )  ->  (
( 2  x.  C
)  /  2 )  =  C )
2614, 15, 25mp3an23 1269 . . 3  |-  ( C  e.  CC  ->  (
( 2  x.  C
)  /  2 )  =  C )
278, 26syl 15 . 2  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  (
( 2  x.  C
)  /  2 )  =  C )
2820, 24, 273eqtrrd 2333 1  |-  ( ( ( A  e.  NN  /\  B  e.  NN  /\  C  e.  NN )  /\  ( ( A ^
2 )  +  ( B ^ 2 ) )  =  ( C ^ 2 )  /\  ( ( A  gcd  B )  =  1  /\ 
-.  2  ||  A
) )  ->  C  =  ( ( M ^ 2 )  +  ( N ^ 2 ) ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    /\ wa 358    /\ w3a 934    = wceq 1632    e. wcel 1696    =/= wne 2459   class class class wbr 4039   ` cfv 5271  (class class class)co 5874   CCcc 8751   0cc0 8753   1c1 8754    + caddc 8756    x. cmul 8758    - cmin 9053    / cdiv 9439   NNcn 9762   2c2 9811   ^cexp 11120   sqrcsqr 11734    || cdivides 12547    gcd cgcd 12701
This theorem is referenced by:  pythagtriplem18  12901
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-13 1698  ax-14 1700  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277  ax-sep 4157  ax-nul 4165  ax-pow 4204  ax-pr 4230  ax-un 4528  ax-cnex 8809  ax-resscn 8810  ax-1cn 8811  ax-icn 8812  ax-addcl 8813  ax-addrcl 8814  ax-mulcl 8815  ax-mulrcl 8816  ax-mulcom 8817  ax-addass 8818  ax-mulass 8819  ax-distr 8820  ax-i2m1 8821  ax-1ne0 8822  ax-1rid 8823  ax-rnegex 8824  ax-rrecex 8825  ax-cnre 8826  ax-pre-lttri 8827  ax-pre-lttrn 8828  ax-pre-ltadd 8829  ax-pre-mulgt0 8830  ax-pre-sup 8831
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-eu 2160  df-mo 2161  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-ne 2461  df-nel 2462  df-ral 2561  df-rex 2562  df-reu 2563  df-rmo 2564  df-rab 2565  df-v 2803  df-sbc 3005  df-csb 3095  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179  df-pss 3181  df-nul 3469  df-if 3579  df-pw 3640  df-sn 3659  df-pr 3660  df-tp 3661  df-op 3662  df-uni 3844  df-iun 3923  df-br 4040  df-opab 4094  df-mpt 4095  df-tr 4130  df-eprel 4321  df-id 4325  df-po 4330  df-so 4331  df-fr 4368  df-we 4370  df-ord 4411  df-on 4412  df-lim 4413  df-suc 4414  df-om 4673  df-xp 4711  df-rel 4712  df-cnv 4713  df-co 4714  df-dm 4715  df-rn 4716  df-res 4717  df-ima 4718  df-iota 5235  df-fun 5273  df-fn 5274  df-f 5275  df-f1 5276  df-fo 5277  df-f1o 5278  df-fv 5279  df-ov 5877  df-oprab 5878  df-mpt2 5879  df-2nd 6139  df-riota 6320  df-recs 6404  df-rdg 6439  df-er 6676  df-en 6880  df-dom 6881  df-sdom 6882  df-sup 7210  df-pnf 8885  df-mnf 8886  df-xr 8887  df-ltxr 8888  df-le 8889  df-sub 9055  df-neg 9056  df-div 9440  df-nn 9763  df-2 9820  df-3 9821  df-n0 9982  df-z 10041  df-uz 10247  df-rp 10371  df-seq 11063  df-exp 11121  df-cj 11600  df-re 11601  df-im 11602  df-sqr 11736  df-abs 11737
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