Question 3:

Prove the following identities: Make sure to show your steps with LS/RS:

a) [3 marks] 12tan x + tan²x =

1-sin 2x

2

cos x

b) [3 marks] (cos x)(cos y) = ½ [cos(x + y) + cos(x − y)]

c) [4 marks]

COS X

1+sinx

+

1+sin x

COS X

= 2sec x

(Source: Ministry of Education (2011). Advanced Functions. Grade 12. University Preparation)

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