Pls prove :
2tan-1x = sin-1(2x/1+x2)

Dear student,

To Prove: 2tan-1x=sin-12x1+x2Taking R.H.Ssin-12x1+x2Put x=tanθ                 ...(1)tan-1x=θ                 ...(2)from (1)we get, sin-12tanθ1+tan2θBut we know that sin2θ=2tanθ1+tan2θ= sin-1 sin2θ=2θPutting the value of θ from (2)=2tan-1x=L.H.Ssince L.H.S=R.H.SHence proved

Regards

  • 9
Let tan-1x= t
tan t = x
sin 2t   =2sin t cos t
            =2{x/(1+x2)1/2}{1/(1+x2)1/2}                 {since, sint = x/1+x2 and cost = 1/1+x2)
            =2x/1+x2
       
2t   =sin-1(2x/1+x2)
2tan-1x =sin-1(2x/1+x2)

Hence, proved.
  • 1
hope i made myself clear

  • 6
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