#### Answer

$$\cos(0^\circ-\theta)=\cos\theta$$

#### Work Step by Step

$$A=\cos(0^\circ-\theta)$$
Apply the cosine difference identity, which states
$$\cos(A-B)=\cos A\cos B+\sin A\sin B$$
we have
$$A=\cos0^\circ\cos\theta+\sin0^\theta\sin\theta$$
$$A=1\times\cos\theta+0\times\sin\theta$$
$$A=\cos\theta$$