HISTORY - Kendriya Vidyalaya Sector 8 - RK Puram New Delhi ...

tanx tan x+ π 3 + tan x+ π 3 tan x- π 3 + tan x- π 3 tanx=-3 . 4.)(i) If . cotx coty=2 , show that cos x+y cos x-y = 1 3 . (ii)If tan A = m.tan B, prove that . sin A-B sin A+B = m-1 m+1 .5.) Prove that: (i) cos 4x=1-8 cos 2 x+8 cos 4 x (ii) sin 4x=4 sin x x cos 3 x-4 cosx sin 3 x (iii) sin 5x=5 sin x -20 sin 3 x+16 sin 5 x ................
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