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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 16172 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → (sin‘𝐴) ∈ ℝ) | |
2 | 1 | sqge0d 14173 | . . . . 5 ⊢ (𝐴 ∈ ℝ → 0 ≤ ((sin‘𝐴)↑2)) |
3 | recoscl 16173 | . . . . . . 7 ⊢ (𝐴 ∈ ℝ → (cos‘𝐴) ∈ ℝ) | |
4 | 3 | resqcld 14161 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ∈ ℝ) |
5 | 1 | resqcld 14161 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → ((sin‘𝐴)↑2) ∈ ℝ) |
6 | 4, 5 | addge02d 11849 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (0 ≤ ((sin‘𝐴)↑2) ↔ ((cos‘𝐴)↑2) ≤ (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)))) |
7 | 2, 6 | mpbid 232 | . . . 4 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ≤ (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2))) |
8 | recn 11242 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℂ) | |
9 | sincossq 16208 | . . . . . 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 14230 | . . . . 5 ⊢ (1↑2) = 1 | |
12 | 10, 11 | eqtr4di 2792 | . . . 4 ⊢ (𝐴 ∈ ℝ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = (1↑2)) |
13 | 7, 12 | breqtrd 5173 | . . 3 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴)↑2) ≤ (1↑2)) |
14 | 1re 11258 | . . . . . 6 ⊢ 1 ∈ ℝ | |
15 | 0le1 11783 | . . . . . 6 ⊢ 0 ≤ 1 | |
16 | lenegsq 15355 | . . . . . 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 11764 | . . . . . . 7 ⊢ (((cos‘𝐴) ∈ ℝ ∧ 1 ∈ ℝ) → (-(cos‘𝐴) ≤ 1 ↔ -1 ≤ (cos‘𝐴))) | |
19 | 14, 18 | mpan2 691 | . . . . . 6 ⊢ ((cos‘𝐴) ∈ ℝ → (-(cos‘𝐴) ≤ 1 ↔ -1 ≤ (cos‘𝐴))) |
20 | 19 | anbi2d 630 | . . . . 5 ⊢ ((cos‘𝐴) ∈ ℝ → (((cos‘𝐴) ≤ 1 ∧ -(cos‘𝐴) ≤ 1) ↔ ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴)))) |
21 | 17, 20 | bitr3d 281 | . . . 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 232 | . 2 ⊢ (𝐴 ∈ ℝ → ((cos‘𝐴) ≤ 1 ∧ -1 ≤ (cos‘𝐴))) |
24 | 23 | ancomd 461 | 1 ⊢ (𝐴 ∈ ℝ → (-1 ≤ (cos‘𝐴) ∧ (cos‘𝐴) ≤ 1)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1536 ∈ wcel 2105 class class class wbr 5147 ‘cfv 6562 (class class class)co 7430 ℂcc 11150 ℝcr 11151 0cc0 11152 1c1 11153 + caddc 11155 ≤ cle 11293 -cneg 11490 2c2 12318 ↑cexp 14098 sincsin 16095 cosccos 16096 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-10 2138 ax-11 2154 ax-12 2174 ax-ext 2705 ax-rep 5284 ax-sep 5301 ax-nul 5311 ax-pow 5370 ax-pr 5437 ax-un 7753 ax-inf2 9678 ax-cnex 11208 ax-resscn 11209 ax-1cn 11210 ax-icn 11211 ax-addcl 11212 ax-addrcl 11213 ax-mulcl 11214 ax-mulrcl 11215 ax-mulcom 11216 ax-addass 11217 ax-mulass 11218 ax-distr 11219 ax-i2m1 11220 ax-1ne0 11221 ax-1rid 11222 ax-rnegex 11223 ax-rrecex 11224 ax-cnre 11225 ax-pre-lttri 11226 ax-pre-lttrn 11227 ax-pre-ltadd 11228 ax-pre-mulgt0 11229 ax-pre-sup 11230 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1539 df-fal 1549 df-ex 1776 df-nf 1780 df-sb 2062 df-mo 2537 df-eu 2566 df-clab 2712 df-cleq 2726 df-clel 2813 df-nfc 2889 df-ne 2938 df-nel 3044 df-ral 3059 df-rex 3068 df-rmo 3377 df-reu 3378 df-rab 3433 df-v 3479 df-sbc 3791 df-csb 3908 df-dif 3965 df-un 3967 df-in 3969 df-ss 3979 df-pss 3982 df-nul 4339 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4912 df-int 4951 df-iun 4997 df-br 5148 df-opab 5210 df-mpt 5231 df-tr 5265 df-id 5582 df-eprel 5588 df-po 5596 df-so 5597 df-fr 5640 df-se 5641 df-we 5642 df-xp 5694 df-rel 5695 df-cnv 5696 df-co 5697 df-dm 5698 df-rn 5699 df-res 5700 df-ima 5701 df-pred 6322 df-ord 6388 df-on 6389 df-lim 6390 df-suc 6391 df-iota 6515 df-fun 6564 df-fn 6565 df-f 6566 df-f1 6567 df-fo 6568 df-f1o 6569 df-fv 6570 df-isom 6571 df-riota 7387 df-ov 7433 df-oprab 7434 df-mpo 7435 df-om 7887 df-1st 8012 df-2nd 8013 df-frecs 8304 df-wrecs 8335 df-recs 8409 df-rdg 8448 df-1o 8504 df-er 8743 df-pm 8867 df-en 8984 df-dom 8985 df-sdom 8986 df-fin 8987 df-sup 9479 df-inf 9480 df-oi 9547 df-card 9976 df-pnf 11294 df-mnf 11295 df-xr 11296 df-ltxr 11297 df-le 11298 df-sub 11491 df-neg 11492 df-div 11918 df-nn 12264 df-2 12326 df-3 12327 df-n0 12524 df-z 12611 df-uz 12876 df-rp 13032 df-ico 13389 df-fz 13544 df-fzo 13691 df-fl 13828 df-seq 14039 df-exp 14099 df-fac 14309 df-bc 14338 df-hash 14366 df-shft 15102 df-cj 15134 df-re 15135 df-im 15136 df-sqrt 15270 df-abs 15271 df-limsup 15503 df-clim 15520 df-rlim 15521 df-sum 15719 df-ef 16099 df-sin 16101 df-cos 16102 |
This theorem is referenced by: cosbnd2 16215 cos02pilt1 26582 sin2h 37596 cos2h 37597 tan2h 37598 abscosbd 45228 |
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