Datrys {l}{a_{4}=(a_{n}*2)}{a=1}

$$\left\{ \begin{array} { l } { a _ { 4 } = ( a _ { n } \times 2 ) } \\ { a = 1 } \end{array} \right.$$

Datrys ar gyfer a_4, a_n, a (complex solution)

$$a_{4}=2a_{n}$$

$$a_{n}\in \mathrm{C}$$

$$a=1$$

Datrys ar gyfer a_4, a_n, a

$$a_{4}=2a_{n}$$

$$a_{n}\in \mathrm{R}$$

$$a=1$$