x 8.4, 4 Choose the correct option. Justify your choice. (iii) (sec A + tan A) (1 – sin A) sec A (B) sin A (C) cosec A (D) cos A (sec A + tan A) (1 – sin A) = (1/(𝑐𝑜𝑠 𝐴)+sin⁡𝐴/cos⁡〖 𝐴〗 ) (1 −sin⁡〖 𝐴)〗 = ((1+ sin⁡〖 𝐴)〗)/cos⁡〖 𝐴〗 ×(1 −sin⁡〖 𝐴)〗 = ((1+ sin⁡〖 𝐴)(1 −〖 sin〗⁡〖 𝐴)〗〗)/cos⁡〖 𝐴〗 = ((1^2 −〖 sin2〗⁡〖 𝐴)〗)/cos⁡〖 𝐴〗 = ((1 −〖 sin2〗⁡〖 𝐴)〗)/cos⁡〖 𝐴〗 = (𝑐𝑜𝑠2 𝐴)/cos⁡〖 𝐴〗 = cos A Hence, (D) is the correct answer

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.

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