English

If y = tanx+tanx+tanx+....+ ∞, then show that dydx=sec2x2y-1. Find dydx at x = 0. - Mathematics and Statistics

Advertisements
Advertisements

Question

If y = `sqrt(tan x + sqrt(tanx + sqrt(tanx + .... +  ∞)`, then show that `dy/dx = (sec^2x)/(2y - 1)`.

Find `dy/dx` at x = 0.

Sum
Advertisements

Solution

Given that : y = `sqrt(tan x + sqrt(tanx + sqrt(tanx + ...  ∞)`    ...(I)

Squaring both sides, we get

y2 = `tanx + sqrt(tanx + sqrt(tanx + ...  ∞)`, which is same as 

y2 = `tanx + sqrt(tanx + sqrt(tanx + sqrt(tanx + ...  ∞)`

y2 = tan x + y    ...[From (I)]

Differentiate w. r. t. x

`d/dx (y^2) = d/dx (tan x) + dy/dx`

`2y dy/dx - dy/dx` = sec2 x

`(2y - 1) dy/dx` = sec2 x

∴ `dy/dx = (sec^2x)/(2y - 1)`

x = 0, y = 0

`dy/dx = 1/(0 - 1)` = – 1

shaalaa.com
  Is there an error in this question or solution?
2022-2023 (March) Official

RELATED QUESTIONS

Find dy/dx if x sin y + y sin x = 0.


Find `bb(dy/dx)` in the following:

2x + 3y = sin x


Find `bb(dy/dx)` in the following:

`y = sin^(-1)((2x)/(1+x^2))`


if `(x^2 + y^2)^2 = xy` find `(dy)/(dx)`


Show that the derivative of the function f given by 

\[f\left( x \right) = 2 x^3 - 9 x^2 + 12x + 9\], at x = 1 and x = 2 are equal.

Find `"dy"/"dx"` ; if y = cos-1 `("2x" sqrt (1 - "x"^2))`


Find `(dy)/(dx) , "If"   x^3 + y^2 + xy = 10`


Find `(dy)/(dx)` if `y = sin^-1(sqrt(1-x^2))`


Find `"dy"/"dx"`, if : x = `sqrt(a^2 + m^2), y = log(a^2 + m^2)`


Find `"dy"/"dx"` if : x = t2 + t + 1, y = `sin((pit)/2) + cos((pit)/2) "at"  t = 1`


Find `dy/dx` if : x = 2 cos t + cos 2t, y = 2 sin t – sin 2t at t = `pi/(4)`


Find `"dy"/"dx"` if : x = t + 2sin (πt), y = 3t – cos (πt) at t = `(1)/(2)`


Differentiate xx w.r.t. xsix.


If y = eax.sin(bx), show that y2 – 2ay1 + (a2 + b2)y = 0.


If x = a sin t – b cos t, y = a cos t + b sin t, show that `(d^2y)/(dx^2) = -(x^2 + y^2)/(y^3)`.


Find the nth derivative of the following:

`(1)/x`


Find the nth derivative of the following : eax+b 


Find the nth derivative of the following : cos x


Find the nth derivative of the following : y = eax . cos (bx + c)


Choose the correct option from the given alternatives : 

Let `f(1) = 3, f'(1) = -(1)/(3), g(1) = -4 and g'(1) =-(8)/(3).` The derivative of `sqrt([f(x)]^2 + [g(x)]^2` w.r.t. x at x = 1 is 


Choose the correct option from the given alternatives :

If y = sec (tan –1x), then `"dy"/"dx"` at x = 1, is equal to


Differentiate the following w.r.t. x : `sin^2[cot^-1(sqrt((1 + x)/(1 - x)))]`


Differentiate the following w.r.t. x : `cos^-1((sqrt(1 + x) - sqrt(1 - x))/2)`


If `sqrt(y + x) + sqrt(y - x)` = c, show that `"dy"/"dx" = y/x - sqrt(y^2/x^2 - 1)`.


If `xsqrt(1 - y^2) + ysqrt(1 - x^2)` = 1, then show that `"dy"/"dx" = -sqrt((1 - y^2)/(1 - x^2)`.


If sin y = x sin (a + y), then show that `"dy"/"dx" = (sin^2(a + y))/(sina)`.


If `"x"^5 * "y"^7 = ("x + y")^12` then show that, `"dy"/"dx" = "y"/"x"`


If log (x + y) = log (xy) + a then show that, `"dy"/"dx" = (- "y"^2)/"x"^2`.


Find `"dy"/"dx"` if x = `"e"^"3t",  "y" = "e"^(sqrt"t")`.


If x2 + y2 = 1, then `(d^2x)/(dy^2)` = ______.


If x2 + y2 = t + `1/"t"` and x4 + y4 = t2 + `1/"t"^2` then `("d"y)/("d"x)` = ______


If x = a t4 y = 2a t2 then `("d"y)/("d"x)` = ______


If x = sin θ, y = tan θ, then find `("d"y)/("d"x)`.


State whether the following statement is True or False:

If `sqrt(x) + sqrt(y) = sqrt("a")`, then `("d"y)/("d"x) = 1/(2sqrt(x)) + 1/(2sqrt(y)) = 1/(2sqrt("a"))`


Find `dy/dx if, x= e^(3t), y = e^sqrtt`


If log(x+y) = log(xy) + a then show that, `dy/dx = (-y^2)/x^2`


If log(x + y) = log(xy) + a then show that, `dy/dx = (-y^2)/x^2`


If log (x + y) = log (xy) + a then show that, `dy/dx = (−y^2)/x^ 2`


Find `dy/dx if , x = e^(3t) , y = e^sqrtt`


Find `dy / dx` if, x = `e^(3t), y = e^sqrt t` 


Find `dy/dx` if, x = e3t, y = `e^sqrtt`


Find `dy/dx` if, `x = e^(3t), y = e^sqrtt`


Find `dy/dx` if, `x = e^(3t), y = e^(sqrtt)`


If log(x + y) = log(xy) + a then show that, `dy/dx = (-y^2)/x^2`


Find `dy/dx"if", x= e^(3t), y=e^sqrtt`


If log(x + y) = log(xy) + a then show that, `dy/dx = (-y^2)/x^2`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×