## Semiclassical wavefront set

Suppose that $a\in C^{\infty}_{c}(\mathbb{R}^n)$ and $\phi\in C^{\infty}(\mathbb{R}^n)$ are real-valued. How would I show that

$WF_{h}(ae^{\frac{i}{h}\phi})=\{(x,\partial_{x}\phi)|x\in$ supp$(a)\}$ ?

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