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Added link to live plot for errors in all three paraxial approximations |
Clarified range of validity dependence on approximation -- cosine and sine behave differently. |
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:<math> \cos \theta \approx 1 - { \theta^2 \over 2 } \ .</math>
The paraxial approximation is accurate within 0.5% for angles under about 5° for the cosine approximation and 10° for the sine approximation, but its inaccuracy grows significantly for larger angles.<ref>
{{cite web
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