About Lesson
9.1 Basic Trigonometric Identities 基本三角关系式
1. Prove that 试证
(a)
(b)
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(c) 

(d) 

(e) 

(f) 

(g) 

(2)
If
, prove that
If


若 , 证明
(3)
If
, show that
If


若 , 证明
(4)
If
, find the values of
若
, 求下列各式的值
(a) sin A cos A
(b) tan A + cot A
If

若

(a) sin A cos A
(b) tan A + cot A
Answer 答案:
(a)

(b)
(5)
If
, then find the value of 
若
则求
之值
If


若


Answer 答案:

(6)
Given that
, find
, if 
已知
, 求
, 当
Given that



已知



Answer 答案:

(7)
Given that
,
, prove that
.
Given that



已知 ,
, 证明
.
(8)
If
show that
If


若 证明