What is the value of (sin 18°)/(cos 72°)?
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0
Without using trigonometric tables, prove that:
(i) sin 53∘ cos 37∘+cos 53∘ sin 37∘=1
(ii) cos 54∘ cos 36∘−sin 54∘ sin 36∘=0
(iii) sec 70∘ sin 20∘+cos 20∘ cosec 70∘=2
(iv) sin 35∘ sin 55∘−cos 35∘ cos 55∘=0
(v) (sin 72∘+cos 18∘)(sin 72∘−cos 18∘)=0
(vi) tan 48∘ tan 23∘ tan 42∘ tan 67∘=1