\( a=\sin 16^{\circ}-\sin 216^{\circ} ; \) \( b=\cos 130^{\circ}-\cos 296^{\circ} ; \) \( c=\operatorname{tg} 140^{\circ}-\operatorname{tg} 220^{\circ} \quad \) sonlarining ishoralarini aniqlang. \( \begin{array}{ll}\text { A) }+;+;+ & \mathrm{B})+;-;+ \\ \text { C) }-;-;+ & \mathrm{D})+;-;-\end{array} \)

Berilgan ifodalar uchun ishoralarni aniqlash uchun har bir ifodaning qiymatini taxminan hisoblaymiz. 1. **\( a = \sin 16^{\circ} - \sin 216^{\circ} \)** \[ \sin 16^{\circ} \approx 0.2756 \] \[ \sin 216^{\circ} = \sin (180^{\circ} + 36^{\circ}) = -\sin 36^{\circ} \approx -0.5878 \] Shunday qilib: \[ a \approx 0.2756 - (-0.5878) = 0.2756 + 0.5878 = 0.8634 \] **\(a > 0\)** 2. **\( b = \cos 130^{\circ} - \cos 296^{\circ} \)** \[ \cos 130^{\circ} = \cos (180^{\circ} - 50^{\circ}) = -\cos 50^{\circ} \approx -0.6428 \] \[ \cos 296^{\circ} = \cos (360^{\circ} - 64^{\circ}) = \cos 64^{\circ} \approx 0.4384 \] Shunday qilib: \[ b \approx -0.6428 - 0.4384 = -1.0812 \] **\(b < 0\)** 3. **\( c = \tan 140^{\circ} - \tan 220^{\circ} \)** \[ \tan 140^{\circ} = \tan (180^{\circ} - 40^{\circ}) = -\tan 40^{\circ} \approx -0.8391 \] \[ \tan 220^{\circ} = \tan (180^{\circ} + 40^{\circ}) = \tan 40^{\circ} \approx 0.8391 \] Shunday qilib: \[ c \approx -0.8391 - 0.8391 = -1.6782 \] **\(c < 0\)** **Xulosa:** - \( a > 0 \) - \( b < 0 \) - \( c < 0 \) To'g'ri javob: **D) +; −; −**