English

State whether the following statement is True or False: If the function f(x) = x2 + 2x – 5 is an increasing function, then x < – 1

Advertisements
Advertisements

Question

State whether the following statement is True or False: 

If the function f(x) = x2 + 2x – 5 is an increasing function, then x < – 1

Options

  • True

  • False

MCQ
True or False
Advertisements

Solution

False 

shaalaa.com
  Is there an error in this question or solution?
Chapter 1.4: Applications of Derivatives - Q.3

RELATED QUESTIONS

Show that the function given by f(x) = sin x is

  1. strictly increasing in `(0, pi/2)`
  2. strictly decreasing in `(pi/2, pi)`
  3. neither increasing nor decreasing in (0, π)

Find the intervals in which the following functions are strictly increasing or decreasing:

x2 + 2x − 5


Find the values of x for  `y = [x(x - 2)]^2` is an increasing function.


Find the intervals in which the function f given by `f(x) = (4sin x - 2x - x cos x)/(2 + cos x)` is (i) increasing (ii) decreasing.


Prove that f(x) = ax + b, where a, b are constants and a > 0 is an increasing function on R ?


Show that f(x) = \[\frac{1}{x}\] is a decreasing function on (0, ∞) ?


Find the interval in which the following function are increasing or decreasing  f(x) = x4 − 4x3 + 4x2 + 15 ?


Show that f(x) = tan x is an increasing function on (−π/2, π/2) ?


Prove that the following function is increasing on R f \[(x) =\]3 \[x^5\] + 40 \[x^3\] + 240\[x\] ?


Find the interval in which f(x) is increasing or decreasing f(x) = sinx + |sin x|, 0 < x \[\leq 2\pi\] ?


Find the interval in which f(x) is increasing or decreasing f(x) = sinx(1 + cosx), 0 < x < \[\frac{\pi}{2}\] ?


What are the values of 'a' for which f(x) = ax is increasing on R ?


Write the interval in which f(x) = sin x + cos x, x ∈ [0, π/2] is increasing ?


The function \[f\left( x \right) = \log_e \left( x^3 + \sqrt{x^6 + 1} \right)\] is of the following types:


Function f(x) = x3 − 27x + 5 is monotonically increasing when ______.


Let ϕ(x) = f(x) + f(2a − x) and f"(x) > 0 for all x ∈ [0, a]. Then, ϕ (x)


Find the value of x, such that f(x) is increasing function.

f(x) = x2 + 2x - 5 


For manufacturing x units, labour cost is 150 – 54x and processing cost is x2. Price of each unit is p = 10800 – 4x2. Find the values of x for which Revenue is increasing.


Let f(x) = x3 − 6x2 + 9𝑥 + 18, then f(x) is strictly decreasing in ______


Show that the function f(x) = x3 + 10x + 7 for x ∈ R is strictly increasing


Test whether the function f(x) = x3 + 6x2 + 12x − 5 is increasing or decreasing for all x ∈ R


The total cost function for production of articles is given as C = 100 + 600x – 3x2, then the values of x for which the total cost is decreasing is  ______


The function f(x) = x3 - 3x is ______.


The function f(x) = tanx – x ______.


The function f (x) = x2, for all real x, is ____________.


If f(x) = sin x – cos x, then interval in which function is decreasing in 0 ≤ x ≤ 2 π, is:


Find the value of x for which the function f(x)= 2x3 – 9x2 + 12x + 2 is decreasing.

Given f(x) = 2x3 – 9x2 + 12x + 2

∴ f'(x) = `squarex^2 - square + square`

∴ f'(x) = `6(x - 1)(square)`

Now f'(x) < 0

∴ 6(x – 1)(x – 2) < 0

Since ab < 0 ⇔a < 0 and b < 0 or a > 0 and b < 0

Case 1: (x – 1) < 0 and (x – 2) < 0

∴ x < `square` and x > `square`

Which is contradiction

Case 2: x – 1 and x – 2 < 0

∴ x > `square` and x < `square`

1 < `square` < 2

f(x) is decreasing if and only if x ∈ `square`


Let f : R `rightarrow` R be a positive increasing function with `lim_(x rightarrow ∞) (f(3x))/(f(x))` = 1 then `lim_(x rightarrow ∞) (f(2x))/(f(x))` = ______.


Find the interval/s in which the function f : R `rightarrow` R defined by f(x) = xex, is increasing.


The function f(x) = sin4x + cos4x is an increasing function if ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×