All the questions in brown circle please , help me

All the questions in brown circle please , help me times me angle. angles of the in Find the values 8. p.. 719. Study ASSIGNMENT p ROBLEMS 1. sin— 1+sin The a quadrilateral on II the mnd with Sino. — . tanA • secA P— 'hat (i) tar-LA -secA sinA COSA eosecO — — cos Prove that — 4S • 3SinX S — z = asin2 x- 2b Sin X X C X — and sinß= , and all x. X c sin2 x , that y — z a — c. a lies in the third quadrant and ß lies in the founh quadrant, find tano W), Cota — N). Show that cos 31 Show that — (cosec2x — cos ec4x) = sin2xsin4x ' 2 sinx cos SX COS 7 X hence prove that sin2x sin 41 sin4x sin 6K sinExsin8x —[cosec2x — cosec(2n + 2)xl. 2 sin x If u, are the of • bsine = c, show that terrns (i) sin a +sinß tan — . sinasinß= prove that 1 +Sin.Z 1 + sin— aå513

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Question 20

To prove:sin20°sin40°sin80°=38LHSsin20°sin40°sin80°=sin20°sin(60°-20°)sin(60°+20°)=sin20°sin260°-sin220°     [using a2-b2=a+ba-b]=sin20°322-sin220°=sin20°34-sin220°=143sin20°-4sin320°=14sin3×20°    [using sin3θ=3sinθ-4sin3θ]=14sin60°= 14×32=38=RHSHence proved

Question 21
To prove:cos6x+6cos4x+15cos2x+10cos5x+5cos3x+10cosx=2cosxTaking LHScos6x+6cos4x+15cos2x+10cos5x+5cos3x+10cosx=cos6x+cos4x+5cos4x+5cos2x+10cos2x+10cos5x+5cos3x+10cosx=cos6x+cos4x+5cos4x+cos2x+10cos2x+1cos5x+5cos3x+10cosx=cos6x+cos4x+5cos4x+cos2x+10cos2x+cos0cos5x+5cos3x+10cosxusing identity cosC+cosD=2cosC+D2cosC-D2=2cos6x+4x2cos6x-4x2+5×2cos4x+2x2cos4x-2x2+10×2cos2x+02cos2x-02cos5x+5cos3x+10cosx=2cos5xcosx+52cos3xcosx+102cosxcosxcos5x+5cos3x+10cosx=2cosxcos5x+5cos3x+10cosxcos5x+5cos3x+10cosx=2cosx=RHSThus, LHS=RHSHence proved
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