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ǰλãҳ > 2018年秋九年级数学下?第二十八?锐角三角函数练习 (新版)新人教版 - 百度文库

2018年秋九年级数学下?第二十八?锐角三角函数练习 (新版)新人教版 - 百度文库

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  • 2025/7/2 5:28:22

⣺(1)CEABECEx RtACEУtanACE1AE2 AE2x. ACx22x25x. 5x35x3. CE3AE6. RtBCEУsinB

22 B45. BCEΪֱΣ BECE3. ABAEBE9. (2)CDDZABϵߣ BD12AB4.5. DEBDBE4.531.5. tanCDECE3DE1.52 tanCDBֵΪ2.

17

28.2.2 Ӧþ

1ʱ ӽйصĽֱӦ

01

֪ʶ1 ýֱν

1. ͼݶ()ּܵĿBC10ףB36㣬AD(DΪױе)ij(C)

A5sin36 B5cos36 C5tan36 D10tan36

1ͼ 2ͼ

2(̲9P743ʽ)ͼijɴڵPϷAA۲⵽ϵԶQ.QAP뾶ΪRɴAPRR. sin3(п)ΪѧУѧѧѵ⣬޽һţŹӵĿ(ƽкӰABMN֮ľ)ͼڲʱѡӶ԰MNϵĵCΪŵһˣںӰAáCAB30㣬غӰABǰ30׺󵽴BBáCBA60.ϲӵĿȣ(οݣ21.4131.73)

⣺CCDABΪD. ߡCAB30㣬 AD3CD. ߡCBA60㣬DB3CD. 33CD30. 3ABADDB303CD1515CD31.7313() 22𣺺ӵĿԼΪ13ף

֪ʶ2 ӽйصʵ 4(̲9P754ʽ)(ɳп)ͼ̽ʾAһ¥BΪ30㣬ⶰ¥ײCĸΪ60㣬A¥ˮƽΪ120 mⶰ¥ĸ߶Ϊ(A)

18

A1603 m B1203 m C300 m

D1602 m

5(п)ͼABCDABBDCDBDAB15 mCD20 mABCD֮һ۳أСAóȪEĸΪ42㣬CEĸΪ45(BEDͬһֱ)֮ľBD(ȷ0.1 mοݣsin420.67cos420.74tan420.90)

⣺⣬áAEB42㣬DEC45. ABBDCDBD RtABEУABE90. AB15AEB42㣬 ABtanAEB BE1550BE150.90. tan423RtDECУCDE90㣬DEC45㣬CD20. EDCD20. 50BDBEED2036.7(m) 3֮ľBDԼΪ36.7 m.

״ 㺯ϵ´ 6(ɳп)ͼΪһ洹ֱOAĸ߶ȣھĵ׶30׵BAǡABOΪOAĸ߶Ϊ(C)

A.30

tan

B30sin C30tan D30cos

19

02 е

7. (п)ij֧һ¥ǰϰͼʾٱݳɹȳCߺ󣬷CϷ17׵Bһߣٱݽȳ֪A¥ˮƽ15ףAõһʩʱˮƽߵļнǡCAD60㣬ڶʩʱˮƽߵļнǡBADĶ(ȷ1)

⣺ӳADBCֱڵE. ⣬BC17ףAE15ףCAE60㣬AEB90㣬 RtACEУtanCAE

CE AECEAEtan60㣽153ף BE17153RtABEУtanBAE AE15BAE71.

𣺵ڶʩʱˮƽߵļнǡBADԼΪ71. 8(п)ڽǿǭߵһҪ̣ABBC(ͼʾ)ǰʦ·ʽ˲˻AϷ97 mP㣬BĸΪ30(ʱCСɽ赲޷۲)˻еBϷDʱܿCʱCΪ8036.

(1)ABijȣ

(2)۲PDˮƽļнΪ30㣬BCij

(Ⱦȷ1 mοݣ31.73sin80360.987cos80360.163tan80366.06)

⣺(1)֪ABP30㣬AP97 AP9797AB973168. tanABPtan3033ABijԼΪ168 m. (2)ߡABP30㣬AP97 PB2PA194. ֡ߡDBCDBA90㣬PBA30㣬 DBPDPB60. PBDǵȱΣ DBPB194. RtBCDУߡC8036䣬 DB194BC32. tanCtan8036

20

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⣺(1)CEABECEx RtACEУtanACE1AE2 AE2x. ACx22x25x. 5x35x3. CE3AE6. RtBCEУsinB22 B45. BCEΪֱΣ BECE3. ABAEBE9. (2)CDDZABϵߣ BD12AB4.5. DEBDBE4.531.5. tanCDECE3DE1.52 tanCDBֵΪ2. 17 28.2.2 Ӧþ 1ʱ ӽйصĽֱӦ 01 ֪ʶ1 ýֱν 1. ͼ

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