Given that θ \theta\,θ is small and is measured in radians, use the small angle approximations to show that
sin5θ+cos2θ≈1+5θ−2θ2\sin 5\theta + \cos 2\theta \approx 1 + 5\theta - 2\theta^2sin5θ+cos2θ≈1+5θ−2θ2