State whether the following are true or false and justify: (9) The value of 2sinθ can be a + 1/a, where a is…

State whether the following are true or false and justify: (9) The value of $2\sin \theta$ can be $a+\frac{1}{a}$, where $a$ is a positive number and $a\ne 1$. (10) $\cos \theta =\frac{a^2+b^2}{2ab}$, where $a$ and $b$ are two distinct numbers such that $ab>0$.