Q3 of 34 Page 189

If tan 2A = cot (A – 18°), where 2A is an acute angle, find the value of A

tan 2A = cot (90° – 2A)

Hence,


90° – 2A = A – 18°


108° – 2A = A


3A = 108°


A = 108/3 = 36°


More from this chapter

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1

Evaluate:

(i)


(ii)


(iii) Cos 48° – sin 42°


(iv) Cosec 31° – sec 59°

 2

Show that:

(i) tan 48° tan 23° tan 42° tan 67° = 1

(ii) cos 38° Cos 52° – sin 38° sin 52° = 0

 4

If tan A = cot B, prove that A + B = 90°

 5

If sec 4A = cosec (A – 20°), where 4A is an acute angle, find the value of A