$h$ is a trigonometric function of the form $h(x)=a\cos(bx+c)+d$. Below is the graph of $h(x)$. The function has a maximum point at $(-2\pi,3)$ and a minimum point at $\left(-\dfrac{\pi}{2},-4\right)$. **Find a formula for $h(x)$. Give an exact expression.** $\qquad h(x)=$ [[☃ expression 1]] $\qquad$