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Mirrors > Home > MPE Home > Th. List > cosbnd | Structured version Visualization version GIF version |
Description: The cosine of a real number lies between -1 and 1. Equation 18 of [Gleason] p. 311. (Contributed by NM, 16-Jan-2006.) |
Ref | Expression |
---|---|
cosbnd | ⊢ (𝐴 ∈ ℝ → (-1 ≤ (cos‘𝐴) ∧ (cos‘𝐴) ≤ 1)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | resincl 15860 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → (sin‘𝐴) ∈ ℝ) | |
2 | 1 | sqge0d 13977 | . . . . 5 ⊢ (𝐴 ∈ ℝ → 0 ≤ ((sin‘𝐴)↑2)) |
3 | recoscl 15861 | . . . . . . 7 ⊢ (𝐴 ∈ ℝ → (cos‘𝐴) ∈ ℝ) | |
4 | 3 | resqcld 13976 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ∈ ℝ) |
5 | 1 | resqcld 13976 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → ((sin‘𝐴)↑2) ∈ ℝ) |
6 | 4, 5 | addge02d 11575 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (0 ≤ ((sin‘𝐴)↑2) ↔ ((cos‘𝐴)↑2) ≤ (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)))) |
7 | 2, 6 | mpbid 231 | . . . 4 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ≤ (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2))) |
8 | recn 10972 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℂ) | |
9 | sincossq 15896 | . . . . . 6 ⊢ (𝐴 ∈ ℂ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = 1) | |
10 | 8, 9 | syl 17 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = 1) |
11 | sq1 13923 | . . . . 5 ⊢ (1↑2) = 1 | |
12 | 10, 11 | eqtr4di 2798 | . . . 4 ⊢ (𝐴 ∈ ℝ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = (1↑2)) |
13 | 7, 12 | breqtrd 5105 | . . 3 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ≤ (1↑2)) |
14 | 1re 10986 | . . . . . 6 ⊢ 1 ∈ ℝ | |
15 | 0le1 11509 | . . . . . 6 ⊢ 0 ≤ 1 | |
16 | lenegsq 15043 | . . . . . 6 ⊢ (((cos‘𝐴) ∈ ℝ ∧ 1 ∈ ℝ ∧ 0 ≤ 1) → (((cos‘𝐴) ≤ 1 ∧ -(cos‘𝐴) ≤ 1) ↔ ((cos‘𝐴)↑2) ≤ (1↑2))) | |
17 | 14, 15, 16 | mp3an23 1452 | . . . . 5 ⊢ ((cos‘𝐴) ∈ ℝ → (((cos‘𝐴) ≤ 1 ∧ -(cos‘𝐴) ≤ 1) ↔ ((cos‘𝐴)↑2) ≤ (1↑2))) |
18 | lenegcon1 11490 | . . . . . . 7 ⊢ (((cos‘𝐴) ∈ ℝ ∧ 1 ∈ ℝ) → (-(cos‘𝐴) ≤ 1 ↔ -1 ≤ (cos‘𝐴))) | |
19 | 14, 18 | mpan2 688 | . . . . . 6 ⊢ ((cos‘𝐴) ∈ ℝ → (-(cos‘𝐴) ≤ 1 ↔ -1 ≤ (cos‘𝐴))) |
20 | 19 | anbi2d 629 | . . . . 5 ⊢ ((cos‘𝐴) ∈ ℝ → (((cos‘𝐴) ≤ 1 ∧ -(cos‘𝐴) ≤ 1) ↔ ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴)))) |
21 | 17, 20 | bitr3d 280 | . . . 4 ⊢ ((cos‘𝐴) ∈ ℝ → (((cos‘𝐴)↑2) ≤ (1↑2) ↔ ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴)))) |
22 | 3, 21 | syl 17 | . . 3 ⊢ (𝐴 ∈ ℝ → (((cos‘𝐴)↑2) ≤ (1↑2) ↔ ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴)))) |
23 | 13, 22 | mpbid 231 | . 2 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴))) |
24 | 23 | ancomd 462 | 1 ⊢ (𝐴 ∈ ℝ → (-1 ≤ (cos‘𝐴) ∧ (cos‘𝐴) ≤ 1)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 396 = wceq 1542 ∈ wcel 2110 class class class wbr 5079 ‘cfv 6432 (class class class)co 7272 ℂcc 10880 ℝcr 10881 0cc0 10882 1c1 10883 + caddc 10885 ≤ cle 11021 -cneg 11217 2c2 12039 ↑cexp 13793 sincsin 15784 cosccos 15785 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1975 ax-7 2015 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2711 ax-rep 5214 ax-sep 5227 ax-nul 5234 ax-pow 5292 ax-pr 5356 ax-un 7583 ax-inf2 9387 ax-cnex 10938 ax-resscn 10939 ax-1cn 10940 ax-icn 10941 ax-addcl 10942 ax-addrcl 10943 ax-mulcl 10944 ax-mulrcl 10945 ax-mulcom 10946 ax-addass 10947 ax-mulass 10948 ax-distr 10949 ax-i2m1 10950 ax-1ne0 10951 ax-1rid 10952 ax-rnegex 10953 ax-rrecex 10954 ax-cnre 10955 ax-pre-lttri 10956 ax-pre-lttrn 10957 ax-pre-ltadd 10958 ax-pre-mulgt0 10959 ax-pre-sup 10960 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1545 df-fal 1555 df-ex 1787 df-nf 1791 df-sb 2072 df-mo 2542 df-eu 2571 df-clab 2718 df-cleq 2732 df-clel 2818 df-nfc 2891 df-ne 2946 df-nel 3052 df-ral 3071 df-rex 3072 df-reu 3073 df-rmo 3074 df-rab 3075 df-v 3433 df-sbc 3721 df-csb 3838 df-dif 3895 df-un 3897 df-in 3899 df-ss 3909 df-pss 3911 df-nul 4263 df-if 4466 df-pw 4541 df-sn 4568 df-pr 4570 df-op 4574 df-uni 4846 df-int 4886 df-iun 4932 df-br 5080 df-opab 5142 df-mpt 5163 df-tr 5197 df-id 5490 df-eprel 5496 df-po 5504 df-so 5505 df-fr 5545 df-se 5546 df-we 5547 df-xp 5596 df-rel 5597 df-cnv 5598 df-co 5599 df-dm 5600 df-rn 5601 df-res 5602 df-ima 5603 df-pred 6201 df-ord 6268 df-on 6269 df-lim 6270 df-suc 6271 df-iota 6390 df-fun 6434 df-fn 6435 df-f 6436 df-f1 6437 df-fo 6438 df-f1o 6439 df-fv 6440 df-isom 6441 df-riota 7229 df-ov 7275 df-oprab 7276 df-mpo 7277 df-om 7708 df-1st 7825 df-2nd 7826 df-frecs 8089 df-wrecs 8120 df-recs 8194 df-rdg 8233 df-1o 8289 df-er 8490 df-pm 8610 df-en 8726 df-dom 8727 df-sdom 8728 df-fin 8729 df-sup 9189 df-inf 9190 df-oi 9257 df-card 9708 df-pnf 11022 df-mnf 11023 df-xr 11024 df-ltxr 11025 df-le 11026 df-sub 11218 df-neg 11219 df-div 11644 df-nn 11985 df-2 12047 df-3 12048 df-n0 12245 df-z 12331 df-uz 12594 df-rp 12742 df-ico 13096 df-fz 13251 df-fzo 13394 df-fl 13523 df-seq 13733 df-exp 13794 df-fac 13999 df-bc 14028 df-hash 14056 df-shft 14789 df-cj 14821 df-re 14822 df-im 14823 df-sqrt 14957 df-abs 14958 df-limsup 15191 df-clim 15208 df-rlim 15209 df-sum 15409 df-ef 15788 df-sin 15790 df-cos 15791 |
This theorem is referenced by: cosbnd2 15903 cos02pilt1 25693 sin2h 35776 cos2h 35777 tan2h 35778 abscosbd 42799 |
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