Question

prove that sin a - 2sin cube a / 2cos cube a- cos a = tan a

Answer 1

sin a - 2sin^3a/2cos^3a- cos a
sin a(1-2sin^2a)/cos a(2cos^2a-1)
sin a*cos2a/cos a*cos2a
sin a/cos a
tan a

Answer 2

Answer:

Step-by-step explanation:

(sinA - 2.sin^3A)/(2cos^3A-cosA)= tanA.

L.H.S.

=sinA(1–2.sin^2A)/cosa(2cos^2A-1)

=sinA.(1–2.sin^2A)/cosA{2(1-sin^2A)-1}

=sinA(1–2sin^2A)/cosa.(2–2sin^2A-1)

=sinA.(1–2sin^2A)/cosA.(1–2sin^2A)

= sinA/cosA

=tanA. Proved.

HAPPY!!!