Metamath Proof Explorer


Theorem dvsid

Description: Derivative of the identity function on the real or complex numbers. (Contributed by Steve Rodriguez, 11-Nov-2015)

Ref Expression
Assertion dvsid SSDIS=S×1

Proof

Step Hyp Ref Expression
1 fnresi IFn
2 rnresi ranI=
3 2 eqimssi ranI
4 df-f I:IFnranI
5 1 3 4 mpbir2an I:
6 5 jctr SSI:
7 recnprss SS
8 dvid DI=×1
9 8 dmeqi domI=dom×1
10 1ex 1V
11 10 fconst ×1:1
12 11 fdmi dom×1=
13 9 12 eqtri domI=
14 7 13 sseqtrrdi SSdomI
15 ssid
16 14 15 jctil SSdomI
17 dvres3 SI:SdomISDIS=IS
18 6 16 17 syl2anc SSDIS=IS
19 7 resabs1d SIS=IS
20 19 oveq2d SSDIS=SDIS
21 8 reseq1i IS=×1S
22 xpssres S×1S=S×1
23 21 22 eqtrid SIS=S×1
24 7 23 syl SIS=S×1
25 18 20 24 3eqtr3d SSDIS=S×1