Advertisements
Advertisements
प्रश्न
Let f(x) = x|x|, for all x ∈ R. Discuss the derivability of f(x) at x = 0
Advertisements
उत्तर
We may rewrite f as f(x) = `{{:(x^2",", "if" x ≥ 0),(-x^2",", "if" x < 0):}`
Now Lf ′(0) = `lim_("h" -> 0^-) ("f"(0 + "h") - "f"(0))/"h"`
= `lim_("h" -> 0^-) (-"h"^2 - 0)/"h"`
= `lim_("h" -> 0^-) - "h"`
= 0
Now Rf ′(0) = `lim_("h" -> 0^+) ("f"(0 + "h") - "f"(0))/"h"`
= `lim_("h" -> 0^+) ("h"^2 - 0)/"h"`
= `lim_("h" -> 0^+) "h"`
= 0
Since the left hand derivative and right hand derivative both are equal, hence f is differentiable at x = 0.
APPEARS IN
संबंधित प्रश्न
Differentiate the function with respect to x.
cos (sin x)
Differentiate the function with respect to x.
`sec(tan (sqrtx))`
Differentiate the function with respect to x.
`(sin (ax + b))/cos (cx + d)`
Differentiate the function with respect to x.
`cos (sqrtx)`
Differentiate the function with respect to x:
sin3 x + cos6 x
Differentiate the function with respect to x:
`sin^(–1)(xsqrtx), 0 ≤ x ≤ 1`
Differentiate the function with respect to x:
`(cos^(-1) x/2)/sqrt(2x+7)`, −2 < x < 2
Find `dy/dx`, if y = 12 (1 – cos t), x = 10 (t – sin t), `-pi/2 < t < pi/2`.
If f(x) = |x|3, show that f"(x) exists for all real x and find it.
Show that the function f(x) = |sin x + cos x| is continuous at x = π.
sinx2 + sin2x + sin2(x2)
`sin^-1 1/sqrt(x + 1)`
(sin x)cosx
(x + 1)2(x + 2)3(x + 3)4
`cos^-1 ((sinx + cosx)/sqrt(2)), (-pi)/4 < x < pi/4`
`tan^-1 (sqrt((1 - cosx)/(1 + cosx))), - pi/4 < x < pi/4`
The differential coefficient of `"tan"^-1 ((sqrt(1 + "x") - sqrt (1 - "x"))/(sqrt (1+ "x") + sqrt (1 - "x")))` is ____________.
If `"f"("x") = ("sin" ("e"^("x"-2) - 1))/("log" ("x" - 1)), "x" ne 2 and "f" ("x") = "k"` for x = 2, then value of k for which f is continuous is ____________.
The rate of increase of bacteria in a certain culture is proportional to the number present. If it doubles in 5 hours then in 25 hours, its number would be
`d/(dx)[sin^-1(xsqrt(1 - x) - sqrt(x)sqrt(1 - x^2))]` is equal to
If `ysqrt(1 - x^2) + xsqrt(1 - y^2)` = 1, then prove that `(dy)/(dx) = - sqrt((1 - y^2)/(1 - x^2))`
Let c, k ∈ R. If f(x) = (c + 1)x2 + (1 – c2)x + 2k and f(x + y) = f(x) + f(y) – xy, for all x, y ∈ R, then the value of |2(f(1) + f(2) + f(3) + ... + f(20))| is equal to ______.
Let f: R→R and f be a differentiable function such that f(x + 2y) = f(x) + 4f(y) + 2y(2x – 1) ∀ x, y ∈ R and f’(0) = 1, then f(3) + f’(3) is ______.
If f(x) = `{{:((sin(p + 1)x + sinx)/x,",", x < 0),(q,",", x = 0),((sqrt(x + x^2) - sqrt(x))/(x^(3//2)),",", x > 0):}`
is continuous at x = 0, then the ordered pair (p, q) is equal to ______.
The function f(x) = x | x |, x ∈ R is differentiable ______.
Prove that the greatest integer function defined by f(x) = [x], 0 < x < 3 is not differentiable at x = 1 and x = 2.
If \[u\] and \[v\] are differentiable functions, what is \[(uv)'\]?
What is \[\frac{d}{dx}(x^n)\]?
What is \[\frac{d}{dx}(\tan x)\]?
A function is differentiable at \[x=c\] when which condition holds?
What is the practical condition for differentiability at a point?
For differentiability on a closed interval \[[a,b]\], which derivative is considered at \[b\]?
For \[x\ne c\], which identity is used to prove that differentiability implies continuity?
Which conclusion establishes that \[f\] is continuous at \[x=c\]?
What does differentiability at a point mean?
