1、 1 AB C B C A B 75 C 30 A 20 10 C B C B 1 C B CB Rt ADC Rt ADB DC DB CB DB DC CB 20 10 200 AC A AD BC D 2 Rt ADC cos AD AC CAD 200 cos30 100 3 sin 200sin30 100 DC AC CAD Rt ADB tan 100 3tan75 DB AD BAD 100 3tan75 100 CB DB DC 5 3tan75 5 27 20 CB C B 27 2 AF BC AB 30 ABC BE AE 0.1 E EN BC N 45 EBN Rt
2、 ADB 75 30 C B A 2 75 30 C B A 1 B D C F E A N 2 Rt ENB DB BN DN DB BN DN Rt ADB 30 AB 60 ABC sin 30 sin60 15 3 AD AB ABC 25.98 26.0 15 DB BE E EN BC N AE BC AEND 26 NE AD Rt ENB 45 EBN 45 EBN 26.0 BN EN 26.0 15 11 AE AD BN BD AE 11 3 A C CAD A 60 B CBA 0.01m C CE AB E CE CE x BE x 60 Rt BCE EB CE 3x x 60 x 30( 3 81.96 4 90 5 . AB 1 0.75 3 9 . 1 2 25 20 . 1 E. 1 0.75 AE EB = = 4 3 . 3 4 AE=4k BE=3k AB=5k AB=5 k=1 AE=4 . 3 3 1 B A AE ABE . 2. 2 9 80 2. 5 4 5 4 . 5 4 16000 . 5 1.78 2.29 sin27 0.45 cos27 0.89 tan27 0.51 . 3 AB D . 5
