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Without using tables, find the value of \(\cfrac{\sin 20^{\circ}}{\cos 70^{\circ}} + \cfrac{\cos 25^{\circ}}{\sin 65^{\circ}}\)...


Question

Without using tables, find the value of \(\cfrac{\sin 20^{\circ}}{\cos 70^{\circ}} + \cfrac{\cos 25^{\circ}}{\sin 65^{\circ}}\)

Options

A) 2

B) 1

C) 0

D) -1

E) -2

The correct answer is A.

Explanation:

Note: sin20o = cos70o hence
sin 20o/cos 70o
+
cos 25o/sin 65o

cos25o = sin65o = 1 + 1 = 2

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