გადაწყვიტეთ {l}{a^2=b^2+c^2-2bccosA}{a=10}{b=20}{cosA=1/2}

$$\left\{ \begin{array} { l } { a ^ { 2 } = b ^ { 2 } + c ^ { 2 } - 2 b c \cos A } \\ { a = 10 } \\ { b = 20 } \\ { \cos A = \frac { 1 } { 2 } } \end{array} \right.$$

ამოხსნა a, b, c, A-ისთვის

$$a=10\text{, }b=20\text{, }c=-10\sqrt{2}i+10\approx 10-14.142135624i\text{, }A=2\pi n_{1}+\frac{5\pi }{3}\text{, }n_{1}\in \mathrm{Z}$$

$$a=10\text{, }b=20\text{, }c=-10\sqrt{2}i+10\approx 10-14.142135624i\text{, }A=2\pi n_{2}+\frac{\pi }{3}\text{, }n_{2}\in \mathrm{Z}$$

$$a=10\text{, }b=20\text{, }c=10+10\sqrt{2}i\approx 10+14.142135624i\text{, }A=2\pi n_{1}+\frac{5\pi }{3}\text{, }n_{1}\in \mathrm{Z}$$

$$a=10\text{, }b=20\text{, }c=10+10\sqrt{2}i\approx 10+14.142135624i\text{, }A=2\pi n_{2}+\frac{\pi }{3}\text{, }n_{2}\in \mathrm{Z}$$