If 2x = y${^{{1 \over 5}}}$ + y${^{ - {1 \over 5}}}$ and (x2 $-$ 1) ${{{d^2}y} \over {d{x^2}}}$ + $\lambda $x ${{dy} \over {dx}}$ + ky = 0, then $\lambda $ + k is equal to :

Question

If 2x = y${^{{1 \over 5}}}$ + y${^{ - {1 \over 5}}}$ and

(x² $-$ 1) ${{{d^2}y} \over {d{x^2}}}$ + $\lambda $x ${{dy} \over {dx}}$ + ky = 0,

then $\lambda $ + k is equal to :

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