About Lesson
(1)
Given that
, where
;
, where
, find the value of
.
已知
, 且
; , 且
, 求
的值.
Given that





已知




Answer:

(2)
Prove that
证明
Prove that

证明

(3)
Show that, if
, 
试证,若
, 
Show that, if


试证,若


(4)
If
and
are the roots of equation
, find the value of
.
若
及
为方程式
的根, 求
的值.
If




若




Answer:

(5)
If A + B = 90
If A + B = 90
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
and A > 0
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
, B > 0
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
, prove that tan A tan B = 1.
Hence without using calculator or mathematical tables, find the value of tan 75
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
– tan15
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
.
若A + B = 90
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
和 A > 0
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
, B > 0
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
, 证明 tan A tan B = 1.
据此不用计算机或查表,求 tan 75
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
– tan15
*** QuickLaTeX cannot compile formula: ^{\cirl} *** Error message: Undefined control sequence \cirl. leading text: $^{\cirl
的值.
Answer:

Prove the following identities.
证明下列恒等式
证明下列恒等式
(6)


(7)


(8)


(9)


(10)


(11)


(12)


(13)


(14)


(15)


(16)
Prove that in triangle
试证在三角形ABC中,
Prove that in triangle

试证在三角形ABC中,
