English

If y = xxx...∞, show that dydxdydx=y2x(1-logy)..

Advertisements
Advertisements

Question

If y = `x^(x^(x^(.^(.^.∞))`, then show that `"dy"/"dx" = y^2/(x(1 - logy).`.

Sum
Advertisements

Solution

y = `x^(x^(x^(.^(.^.∞))`
∴ log y = `log(x^(x^(x^(.^(.^.∞)))))`
= `x^(x^(x^(.^(.^.∞)))).logx` 
∴ log y = y log x                       ...(1)
Differentiating both sides w.r.t. x, we get
`(1)/y.dy/dx = y.d/dx(logx) + (logx)dy/dx`

∴ `(1)/ydy/dx = y xx (1)/x + (logx)dy/dx`

∴ `(1/y - logx)dy/dx = y/x`

∴ `((1 - ylogx)/(y))dy/dx"= y/x`

∴ `dy/dx = y^2/(x(1 - ylogx)`

∴ `dy/dx = y^2/(x(1 - logy)`.                 ...[By (1)]

shaalaa.com
  Is there an error in this question or solution?
Chapter 1: Differentiation - Exercise 1.3 [Page 40]

RELATED QUESTIONS

 

if xx+xy+yx=ab, then find `dy/dx`.


Differentiate the function with respect to x.

`(sin x)^x + sin^(-1) sqrtx`


Differentiate the function with respect to x.

xsin x + (sin x)cos x


Find `bb(dy/dx)` for the given function:

yx = xy


Find `bb(dy/dx)` for the given function:

xy = `e^((x - y))`


Differentiate (x2 – 5x + 8) (x3 + 7x + 9) in three ways mentioned below:

  1. By using the product rule.
  2. By expanding the product to obtain a single polynomial.
  3. By logarithmic differentiation.

Do they all give the same answer?


If u, v and w are functions of x, then show that `d/dx(u.v.w) = (du)/dx v.w + u. (dv)/dx.w + u.v. (dw)/dx` in two ways-first by repeated application of product rule, second by logarithmic differentiation.


Differentiate the function with respect to x:

xx + xa + ax + aa, for some fixed a > 0 and x > 0


If y = `e^(acos^(-1)x)`, −1 ≤ x ≤ 1, show that `(1- x^2) (d^2y)/(dx^2) -x dy/dx - a^2y = 0`.


Find `(dy)/(dx) , if y = sin ^(-1) [2^(x +1 )/(1+4^x)]`


Evaluate 
`int  1/(16 - 9x^2) dx`


Find `(d^2y)/(dx^2)` , if y = log x


If `(sin "x")^"y" = "x" + "y", "find" (d"y")/(d"x")`


If y = (log x)x + xlog x, find `"dy"/"dx".`


If log (x + y) = log(xy) + p, where p is a constant, then prove that `"dy"/"dx" = (-y^2)/(x^2)`.


If `log_5((x^4 + y^4)/(x^4 - y^4)) = 2, "show that""dy"/"dx" = (12x^3)/(13y^3)`.


If x = a cos3t, y = a sin3t, show that `"dy"/"dx" = -(y/x)^(1/3)`.


If x = log(1 + t2), y = t – tan–1t,show that `"dy"/"dx" = sqrt(e^x - 1)/(2)`.


If x = sin–1(et), y = `sqrt(1 - e^(2t)), "show that"  sin x + dy/dx` = 0


If x = `(2bt)/(1 + t^2), y = a((1 - t^2)/(1 + t^2)), "show that" "dx"/"dy" = -(b^2y)/(a^2x)`.


Differentiate 3x w.r.t. logx3.


Find the second order derivatives of the following : x3.logx


If y = log [cos(x5)] then find `("d"y)/("d"x)`


If y = 5x. x5. xx. 55 , find `("d"y)/("d"x)`


Derivative of loge2 (logx) with respect to x is _______.


lf y = `2^(x^(2^(x^(...∞))))`, then x(1 - y logx logy)`dy/dx` = ______  


If xy = ex-y, then `"dy"/"dx"` at x = 1 is ______.


`d/dx(x^{sinx})` = ______ 


`"d"/"dx" [(cos x)^(log x)]` = ______.


If y = `("e"^"2x" sin x)/(x cos x), "then" "dy"/"dx" = ?`


Derivative of `log_6`x with respect 6x to is ______


`lim_("x" -> 0)(1 - "cos x")/"x"^2` is equal to ____________.


Given f(x) = `log((1 + x)/(1 - x))` and g(x) = `(3x + x^3)/(1 + 3x^2)`, then fog(x) equals


If `log_10 ((x^3 - y^3)/(x^3 + y^3))` = 2 then `dy/dx` = ______.


If `log_10 ((x^2 - y^2)/(x^2 + y^2))` = 2, then `dy/dx` is equal to ______.


If y = `9^(log_3x)`, find `dy/dx`.


The derivative of log x with respect to `1/x` is ______.


Find `dy/dx`, if y = (log x)x.


If xy = yx, then find `dy/dx`


If \[y=x^x+x^{\frac{1}{x}}\] then \[\frac{\mathrm{d}y}{\mathrm{d}x}\] is equal to


For which type of function is logarithmic differentiation especially useful?


Which is the derivative of \[\sqrt{\frac{(x-3)(x^2+4)}{3x^2+4x+5}}\]?


For \[y=x^{\sin x}\], \[x>0\], what equation results after taking logarithm on both sides?


After taking logarithms in logarithmic differentiation, which rules are used to simplify products, quotients and powers before differentiation?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×