Mathematics - Application of Derivative Question with Solution | TestHub

Let f be twice differentiable such that ${\mathrm{f}}^{\prime \prime }(\mathrm{x})=-\mathrm{f}(\mathrm{x})$ and ${\mathrm{f}}^{\prime }(\mathrm{x})=\mathrm{g}(\mathrm{x})$. If $\mathrm{h}(\mathrm{x})=(\mathrm{f}(\mathrm{x}){)}^2+(\mathrm{g}(\mathrm{x}){)}^2$, where $\mathrm{h}(5)=9$. Then the value of $\mathrm{h}(10)$ is