English

If log10(x3-y3x3+y3) = 2, show that dydx=-99x2101y2.

Advertisements
Advertisements

Question

If `log_10((x^3 - y^3)/(x^3 + y^3))` = 2, show that `dy/dx = -(99x^2)/(101y^2)`.

Sum
Advertisements

Solution

`log_10((x^3 - y^3)/(x^3 + y^3))` = 2

∴ `(x^3 - y^3)/(x^3 + y^3)` = 102 = 100

∴ x3 – y3 = 100x3 + 100y3

∴ 101y3 = – 99x3

∴ y3 = `(-99)/(101)x^3`

Differentiating both sides w.r.t. x, we get

`3y^2 dy/dx = (-99)/(101) xx 3x^2`

∴ `dy/dx = -(99x^2)/(101y^2`

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.

`sqrt(((x-1)(x-2))/((x-3)(x-4)(x-5)))`


Differentiate the function with respect to x.

`(x + 1/x)^x + x^((1+1/x))`


Differentiate the function with respect to x.

xsin x + (sin x)cos x


Differentiate the function with respect to x.

`(x cos x)^x + (x sin x)^(1/x)`


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

xy + yx = 1


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

yx = xy


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.


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


if `x^m y^n = (x + y)^(m + n)`, prove that `(d^2y)/(dx^2)= 0`


Find `"dy"/"dx"` , if `"y" = "x"^("e"^"x")`


 Solve the following differential equation: (3xy + y2) dx + (x2 + xy) dy = 0 


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 ey = yx, then show that `"dy"/"dx" = (logy)^2/(log y - 1)`.


If x = `asqrt(secθ - tanθ), y = asqrt(secθ + tanθ), "then show that" "dy"/"dx" = -y/x`.


If x = esin3t, y = ecos3t, then show that `dy/dx = -(ylogx)/(xlogy)`.


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 nth derivative of the following: log (ax + b)


If y = A cos (log x) + B sin (log x), show that x2y2 + xy1 + y = 0.


If f(x) = logx (log x) then f'(e) is ______


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


If log5 `((x^4 + "y"^4)/(x^4 - "y"^4))` = 2, show that `("dy")/("d"x) = (12x^3)/(13"y"^2)`


If x7 . y5 = (x + y)12, show that `("d"y)/("d"x) = y/x`


If y = tan-1 `((1 - cos 3x)/(sin 3x))`, then `"dy"/"dx"` = ______.


`d/dx(x^{sinx})` = ______ 


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


If xm . yn = (x + y)m+n, prove that `"dy"/"dx" = y/x`


If y = `log ((1 - x^2)/(1 + x^2))`, then `"dy"/"dx"` is equal to ______.


If `"y" = "e"^(1/2log (1 +  "tan"^2"x")), "then"  "dy"/"dx"` is equal to ____________.


If y `= "e"^(3"x" + 7), "then the value" |("dy")/("dx")|_("x" = 0)` is ____________.


Find `dy/dx`, if y = (sin x)tan x – xlog x.


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


What is logarithmic differentiation?


For which type of function is logarithmic differentiation especially useful?


If \[y=[u(x)]^{v(x)}\], which expression gives \[\frac{dy}{dx}\] in logarithmic differentiation?


After differentiating \[\log y=v(x)\cdot\log[u(x)]\], which equation is obtained?


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


What condition must be ensured for an expression inside logarithm?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×