13
3k/
3k M
C
3K
H
M
k = 5
=
5.510
6.△ABC中,∠B=90°,在AB上,若AD=3,BC=2且∠BAC=∠BC.
C
A 3'D
13
7. 設為銳角,且滿足6cos²-cos0-1=0,求=600
=>
32 cos 0 = x
6x²-x-1=0
8.已知為銳角,且sin cose
(sin & cos 0)²
=> sin² 0 + 005² 0 = 16
9.若銳角滿足sin
=>
sine
=
3
=-
5
,
求
2
6
(3x+1) (2x-1) = 0
二厂
x = 1/3 of 1/1/
sine
,
求
cos A
的值 =
cos e
sine
cos(90°-0)
sin(90°-0)
5
=
6