Pls solve the fifth question asap. Pls solve the fifth question asap. S. li tan A n tan hjn A un is that 6. If 2 sjn A - I O. 'how that sm JA sin A 4 A (ii) If 4 coe A 3 z 0. show that cos 3 A 4 cos' A 7. Evaluate 2 tan 130 cot SS0 2 3 cos A Share with your friends Share 0 Rashi Lokwani answered this Dear Student, Answer 5: sin A = m sin B⇒sin Asin B = m ...(1)tan A = n tan B⇒tan Atan B = n⇒sin A cos Asin Bcos B = n⇒sin A cos A×cos Bsin B = n⇒sin Asin B×cos Bcos A = n{From (1)}⇒ m ×cos Bcos A = n⇒m cos B = n cos A⇒ n cos A = m cos B{Squaring both sides}⇒n cos A2 = m cos B2⇒ n2cos2A = m2 cos2B⇒ n2cos2A = m2(1 - sin2B) {Since, sin2θ + cos2θ = 1 → cos2θ = 1 - sin2θ}⇒ n2cos2A = m2 ( 1 - sin2Am2) {Since, sin Asin B = m → sin B = sin Am → sin2 B = sin2 Am2}⇒ n2cos2A = m2 - sin2A⇒ n2cos2A = m2 - (1 - cos2A) {Since, sin2θ + cos2θ = 1 → sin2θ = 1 - cos2θ}⇒ n2cos2A = m2 - 1 + cos2A⇒ n2cos2A - cos2A = m2 - 1⇒ cos2A (n2 - 1 ) = m2 - 1⇒ cos2A = m2 - 1n2 - 1Hence, proved. Regards 0 View Full Answer