ig `sinB=1/2` then prove that `3cosB-4cos^3B=0`

ig sin B=(1)/(2) then prove that 3cos B-4cos^(3)B=0

If sin B= 1/2 find the value of 3 cosB- 4cos^3B .

If sinA/3=sinB/4=1/5 and A,B are angles in the second quadrant then prove that 4cosA+3cosB=-5

In any triangle ABC If sinA : sinB: sinC=4:5:6,then prove that cos A :cosB: cosC=12:9:2.

i) If sinA+sinB=sqrt(3)(cosB-cosA) , prove that: sin3A+sin3B=0 ii) If A,B and C are in arithmetic progression, then prove that: cotB=(sinA-sinc)/(cosC-cosA)

If sinA=sinB and cosA=cosB , then prove that sin((A-B)/2)=0

In any triangle ABC , prove that a(cosB+cot(A/2).sinB)=b+c .

In sinA=sinB and cos A=cos B , then prove that sin(A-B)/(2)=0

In sinA=sinB and cos A=cos B , then prove that sin((A-B)/2)=0

In a triangle ABC, prove that: cos^4A+cos^4B+cos^4C= 3/2 + 2 cosA cosB cosC+ 1/2 cos 2A cos2B cos2C