WAEC - Mathematics (1995 - No. 41)
Without using tables, find the value of \(\frac{\sin 20°}{\cos 70°} + \frac{\cos 25°}{\sin 65°}\)
2
1
o
-1
-2
คำอธิบาย
Note: sin 20° = cos 70° hence
\(\frac{\sin 20}{\cos 70} = 1\)
Also, cos 65° = sin 25°
\(\frac{\cos 65}{\sin 25} = 1\)
\(\therefore \frac{\sin 20}{\cos 70} + \frac{\cos 65}{\sin 25}\)
= 1 + 1
= 2