Obliczamy sinusy danych kątów, korzystając ze wzorów redukcyjnych. Wartości odpowiednich funkcji sprawdzamy w tabelce.

$\sin \left(-\alpha \right)=-\sin \alpha$

$\sin \left({180}^{\circ }-\alpha \right)=\sin \alpha$

$\sin \left({180}^{\circ }+\alpha \right)=-\sin \alpha$

$\sin \left({90}^{\circ }-\alpha \right)=\cos \alpha$

$\sin \left({90}^{\circ }+\alpha \right)=\cos \alpha$

a)

$\sin {98}^{\circ }=\sin \left({90}^{\circ }+8^{\circ }\right)=\cos 8^{\circ }\approx 0,9903$

$\sin {107}^{\circ }=\sin \left({90}^{\circ }+{17}^{\circ }\right)=\cos {17}^{\circ }\approx 0,9563$

$\sin {173}^{\circ }=\sin \left({180}^{\circ }-7^{\circ }\right)=\sin 7^{\circ }\approx 0,1219$

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b)

$\sin \left(-{16}^{\circ }\right)=-\sin {16}^{\circ }\approx -0,2756$

$\sin \left(-{49}^{\circ }\right)=-\sin {49}^{\circ }\approx -0,7547$

$\sin \left(-{74}^{\circ }\right)=-\sin {74}^{\circ }\approx -0,9613$

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c)

$\sin \left(-{108}^{\circ }\right)=-\sin {108}^{\circ }=-\sin \left({90}^{\circ }+{18}^{\circ }\right)=-\cos {18}^{\circ }\approx -0,9511$

$\sin \left(-{156}^{\circ }\right)=-\sin {156}^{\circ }=-\sin \left({90}^{\circ }+{66}^{\circ }\right)=-\cos {66}^{\circ }\approx -0,4067$

$\sin \left(-{172}^{\circ }\right)=-\sin {172}^{\circ }=-\sin \left({180}^{\circ }-8^{\circ }\right)=-\sin 8^{\circ }\approx -0,1392$

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d)

$\sin \left(-{30}^{\circ }\right)=-\sin {30}^{\circ }=-\frac{1}{2}$

$\sin {120}^{\circ }=\sin \left({90}^{\circ }+{30}^{\circ }\right)=\cos {30}^{\circ }\approx \frac{\sqrt{3}}{2}$

$\sin \left(-{150}^{\circ }\right)=-\sin {150}^{\circ }=-\sin \left({90}^{\circ }+{60}^{\circ }\right)=-\cos {60}^{\circ }\approx -\frac{1}{2}$