Prove that, 1+cosAsinA=sinA1-cosA
In 1+cosAsinA=sinA1-cosA,
L.H.S=1+cosAsinA
Multiplying and dividing the L.H.S by 1-cosA we get,
1+cosAsinA=1+cosAsinAĆ1-cosA1-cosA
=1-cos2AsinA1-cosAā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦āµa+ba-b=a2-b2
=sin2AsinA1-cosAā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦ā¦.āµsin2A+cos2A=1
=sinA1-cosA
=R.H.S
Hence, it is proved that 1+cosAsinA=sinA1-cosA
loge(n+1)−loge(n−1)=4a[(1n)+(13n3)+(15n5)+...∞] Find 8a.