0∘≤θ<90∘0^{\circ} \leq \theta<90^{\circ}0∘≤θ<90∘
0∘<θ<90∘0^{\circ}<\theta<90^{\circ}0∘<θ<90∘
0∘≤θ≤90∘0^{\circ} \leq \theta \leq 90^{\circ}0∘≤θ≤90∘
0∘<θ≤90∘0^{\circ}<\theta \leq 90^{\circ}0∘<θ≤90∘
