यदि ` y= (cos x)^(cos x^( cos x )...infty ) ,` तब सिद्ध कीजिये की
` " "(dy)/(dx) =(y^(2)tan x)/(ylog (cosx )-1)`

Explanation

`y=(cosx )^(y) " "rArr (logy =y log cos x )`
`rArr (1)/(y) (dy)/(dx) =y*(1)/(cos xdx ) (cos x )+ (log (cos x))(dy)/(dx) `
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