The cosine of an acute angle \(\theta\) is \(\frac{\sqrt{11}}{5}\). What is \(\sin(\theta)\)?

Select all statements that are true for all acute angles $\theta$.

Han is trying to prove that $\tan^2(\theta)+1=\dfrac{1}{\cos^2(\theta)}$ for any acute angle $\theta$. He notes that if the side adjacent to angle $\theta$ has length $a$, the side opposite angle $\theta$ has length $o$, and the hypotenuse of the triangle has length $h$, then $\tan(\theta)$ is $\frac{o}{a}$ and $\tan^2(\theta)$ is $\frac{o^2}{a^2}$. He says that means $\tan^2(\theta)+1$ is $\frac{o^2}{a^2}+\frac{a^2}{a^2}$. He claims that expression is equivalent to $\frac{h^2}{a^2}$. Do you agree with his claim? Justify your response.