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 is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.

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