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Theorem cvgratlem1 7193
Description: Lemma for cvgrat 7198. Establish, by induction, an exponential upper bound for the terms of a real series, given that the ratio of successive terms is less than some positive constant A beyond a starting index B.
Hypothesis
Ref Expression
cvgratlem1.1 |- F:NN-->RR
Assertion
Ref Expression
cvgratlem1 |- ((C e. NN /\ ((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x)))))) -> (F` (B + C)) <_ ((A^C) x. (F` B)))
Distinct variable groups:   x,A   x,B   x,F

Proof of Theorem cvgratlem1
StepHypRef Expression
1 opreq2 3960 . . . . . . 7 |- (y = 1 -> (B + y) = (B + 1))
21fveq2d 3719 . . . . . 6 |- (y = 1 -> (F` (B + y)) = (F` (B + 1)))
3 opreq2 3960 . . . . . . 7 |- (y = 1 -> (A^y) = (A^1))
43opreq1d 3966 . . . . . 6 |- (y = 1 -> ((A^y) x. (F` B)) = ((A^1) x. (F` B)))
52, 4breq12d 2626 . . . . 5 |- (y = 1 -> ((F` (B + y)) < ((A^y) x. (F` B)) <-> (F` (B + 1)) < ((A^1) x. (F` B))))
65imbi2d 611 . . . 4 |- (y = 1 -> ((((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + y)) < ((A^y) x. (F` B))) <-> (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + 1)) < ((A^1) x. (F` B)))))
7 opreq2 3960 . . . . . . 7 |- (y = z -> (B + y) = (B + z))
87fveq2d 3719 . . . . . 6 |- (y = z -> (F` (B + y)) = (F` (B + z)))
9 opreq2 3960 . . . . . . 7 |- (y = z -> (A^y) = (A^z))
109opreq1d 3966 . . . . . 6 |- (y = z -> ((A^y) x. (F` B)) = ((A^z) x. (F` B)))
118, 10breq12d 2626 . . . . 5 |- (y = z -> ((F` (B + y)) < ((A^y) x. (F` B)) <-> (F` (B + z)) < ((A^z) x. (F` B))))
1211imbi2d 611 . . . 4 |- (y = z -> ((((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + y)) < ((A^y) x. (F` B))) <-> (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + z)) < ((A^z) x. (F` B)))))
13 opreq2 3960 . . . . . . 7 |- (y = (z + 1) -> (B + y) = (B + (z + 1)))
1413fveq2d 3719 . . . . . 6 |- (y = (z + 1) -> (F` (B + y)) = (F` (B + (z + 1))))
15 opreq2 3960 . . . . . . 7 |- (y = (z + 1) -> (A^y) = (A^(z + 1)))
1615opreq1d 3966 . . . . . 6 |- (y = (z + 1) -> ((A^y) x. (F` B)) = ((A^(z + 1)) x. (F` B)))
1714, 16breq12d 2626 . . . . 5 |- (y = (z + 1) -> ((F` (B + y)) < ((A^y) x. (F` B)) <-> (F` (B + (z + 1))) < ((A^(z + 1)) x. (F` B))))
1817imbi2d 611 . . . 4 |- (y = (z + 1) -> ((((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + y)) < ((A^y) x. (F` B))) <-> (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + (z + 1))) < ((A^(z + 1)) x. (F` B)))))
19 opreq2 3960 . . . . . . 7 |- (y = C -> (B + y) = (B + C))
2019fveq2d 3719 . . . . . 6 |- (y = C -> (F` (B + y)) = (F` (B + C)))
21 opreq2 3960 . . . . . . 7 |- (y = C -> (A^y) = (A^C))
2221opreq1d 3966 . . . . . 6 |- (y = C -> ((A^y) x. (F` B)) = ((A^C) x. (F` B)))
2320, 22breq12d 2626 . . . . 5 |- (y = C -> ((F` (B + y)) < ((A^y) x. (F` B)) <-> (F` (B + C)) < ((A^C) x. (F` B))))
2423imbi2d 611 . . . 4 |- (y = C -> ((((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + y)) < ((A^y) x. (F` B))) <-> (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + C)) < ((A^C) x. (F` B)))))
25 nnret 5885 . . . . . . . . 9 |- (B e. NN -> B e. RR)
26 leidt 5512 . . . . . . . . 9 |- (B e. RR -> B <_ B)
2725, 26syl 10 . . . . . . . 8 |- (B e. NN -> B <_ B)
28 breq2 2618 . . . . . . . . . 10 |- (x = B -> (B <_ x <-> B <_ B))
29 opreq1 3959 . . . . . . . . . . . 12 |- (x = B -> (x + 1) = (B + 1))
3029fveq2d 3719 . . . . . . . . . . 11 |- (x = B -> (F` (x + 1)) = (F` (B + 1)))
31 fveq2 3715 . . . . . . . . . . . 12 |- (x = B -> (F` x) = (F` B))
3231opreq2d 3967 . . . . . . . . . . 11 |- (x = B -> (A x. (F` x)) = (A x. (F` B)))
3330, 32breq12d 2626 . . . . . . . . . 10 |- (x = B -> ((F` (x + 1)) < (A x. (F` x)) <-> (F` (B + 1)) < (A x. (F` B))))
3428, 33imbi12d 625 . . . . . . . . 9 |- (x = B -> ((B <_ x -> (F` (x + 1)) < (A x. (F` x))) <-> (B <_ B -> (F` (B + 1)) < (A x. (F` B)))))
3534rcla4v 1869 . . . . . . . 8 |- (B e. NN -> (A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))) -> (B <_ B -> (F` (B + 1)) < (A x. (F` B)))))
3627, 35mpid 47 . . . . . . 7 |- (B e. NN -> (A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))) -> (F` (B + 1)) < (A x. (F` B))))
3736imp 350 . . . . . 6 |- ((B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x)))) -> (F` (B + 1)) < (A x. (F` B)))
3837adantl 388 . . . . 5 |- (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> (F` (B + 1)) < (A x. (F` B)))
39 recnt 5293 . . . . . . . . 9 |- (A e. RR -> A e. CC)
40 exp1t 6513 . . . . . . . . 9 |- (A e. CC -> (A^1) = A)
4139, 40syl 10 . . . . . . . 8 |- (A e. RR -> (A^1) = A)
4241adantr 389 . . . . . . 7 |- ((A e. RR /\ 0 < A) -> (A^1) = A)
4342opreq1d 3966 . . . . . 6 |- ((A e. RR /\ 0 < A) -> ((A^1) x. (F` B)) = (A x. (F` B)))
4443adantr 389 . . . . 5 |- (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F` x))))) -> ((A^1) x. (F` B)) = (A x. (F` B)))
4538, 44breqtrrd 2636 . . . 4 |- (((A e. RR /\ 0 < A) /\ (B e. NN /\ A.x e. NN (B <_ x -> (F` (x + 1)) < (A x. (F