Introductio in analysin infinitorum

EX CIRCULO ORTIS. 97 tutis, habebuntur hæ æquationes, tanquam totidem Theore- CAP. mata. VIII. $ \mathrm{fin}. a + \mathrm{fin}. b = 2 \mathrm{fin}. \frac{a+b}{2} \mathrm{cof}. \frac{a-b}{2} $ $ \mathrm{fin}. a - \mathrm{fin}. b = 2 \mathrm{cof}. \frac{a+b}{2} \mathrm{fin}. \frac{a-b}{2} $ $ \mathrm{cof}. a + \mathrm{cof}. b = 2 \mathrm{cof}. \frac{a+b}{2} \mathrm{cof}. \frac{a-b}{2} $ $ \mathrm{cof}. b - \mathrm{cof}. a = 2 \mathrm{fin}. \frac{a+b}{2} \mathrm{fin}. \frac{a-b}{2} $ ex his porro nascuntur, ope divisionis, hæc Theoremata $ \frac{\mathrm{fin}. a + \mathrm{fin}. b}{\mathrm{fin}. a - \mathrm{fin}. b} = \mathrm{tang}. \frac{a+b}{2} \mathrm{cot}. \frac{a-b}{2} = \frac{\mathrm{tang}. \frac{a+b}{2}}{\mathrm{tang}. \frac{ [TRUNCATED]