In triangle `A B C ,` prove that `sinA/2+sinB/2+sinC/2lt=3/2dot` Hence, deduce that `cos(pi+A)/4cos(pi+B)/4cos(pi_C)/4lt=1/8`

In a triangle ABC , prove that ,(sinA+sinB)/2lt=sin((A+B)/2)

In triangle ABC, prove that sin((A)/(2))+sin((B)/(2))+sin((C)/(2))<=(3)/(2) Hence,deduce that cos((pi+A)/(4))cos((pi+B)/(4))cos((pi+C)/(4))<=(1)/(8)

Prove that cos((2pi)/7)cos((4pi)/7)cos((8pi)/7)=1/8

Prove that cos((2pi)/7) cos((4pi)/7) cos((8pi)/7) =1/8

If A +B+C = 180^circ , prove that cos A/2+ cos B/2 +cos C/2 = 4cos (pi-A)/4 * cos(pi-B)/4 cos(pi-C)/4

Prove that: cos(pi)/(7)cos(2 pi)/(7)cos(4 pi)/(7)=-(1)/(8)

In triangle ABC,prove that cos((A)/(2))+cos((B)/(2))+cos((C)/(2))=4(cos(pi-A))/(4)(cos(pi-B))/(4)(cos(pi-C))/(4)

Hence deduce that cos(pi)/(9)cos(2 pi)/(9)cos(3 pi)/(9)cos(4 pi)/(9)=(1)/(16)

Prove that 4cos(2 pi)/(7)*cos(pi)/(7)-1=2cos(2 pi)/(7)

Prove that 4cos((2pi)/7).cos(pi/7)-1=2cos((2pi)/7) .