HARD
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Let f:RR be a differentiable function for all values of x and has the property that f(x) and f'(x) have opposite signs for all values of x. Then,

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Important Questions on Application of Derivatives

HARD
Let fx=x+logex-xlogex,x0, . 

   Column 1 contains information about zeros of fx, fx and fx.

   Column 2 contains information about the limiting behaviour of fx, fx and fx at infinity.

   Column 3 contains information about increasing-decreasing nature of fx and fx.
 
Column 1 Column 2 Column 3
(I) fx=0 for some x1, e2 (i) limxfx=0 (P) f is increasing in (0, 1)
(II) fx=0 for some x1, e (ii) limxfx=- (Q) f is decreasing in e, e2
(III) fx=0 for some x0, 1 (iii) limxfx=- (R) f is increasing in (0, 1)
(IV) fx=0 for some x1, e (iv) limxfx=0 (S) f is decreasing in e, e2
Which of the following options is the only Incorrect combination?
MEDIUM
If fx=35x+45x-1, xR, then the equation fx=0 has :
HARD
Let fx=x+logex-xlogex,x0, 
Column 1 contains information about zeros of f( x ) , f'( x ) and f''( x )
Column 2 contains information about the limiting behaviour of f( x ) , f'( x ) and f''( x ) at infinity.
Column 3 contains information about increasing-decreasing nature of f( x ) and f'( x )
Column 1 Column 2 Column 3
(I) fx=0 for some x1, e2 (i) limxfx=0 (P) f is increasing in 0, 1
(II) fx=0 for some x in 1, e (ii) limxfx=- (Q) f is decreasing in e, e2
(III) fx=0 for some x0, 1 (iii) limxfx=- (R) f is increasing in 0,1
(IV) fx=0 for some x1, e (iv) limxfx=0 (S) f is decreasing in e, e2

Which of the following options is the only CORRECT combination?

EASY
If m is the minimum value of k for which the function fx=xkx-x2  is increasing in the interval [0, 3] and M is the maximum value of f in [0, 3] when k=m, then the ordered pair (m, M) is equal to:
HARD
Let fx=210x+1 and gx=310x-1. If fogx=x, then x is equal to:
HARD
Let f:0, 2R be a twice differentiable function such that f''x>0, for all  x0, 2. If ϕx= fx+ f2x, then ϕ is
MEDIUM
Let fx=sin4x+cos4x. Then, f is an increasing function in the interval:
EASY
 The function f(x)=4sin3x-6sin2x+12sinx+100 is strictly
MEDIUM
The function f defined by fx=x3-3x2+5x+7 is:
HARD
The sum of non - real roots of the polynomial equation x3+3x2+3x+3=0 .
MEDIUM
Let fx=ex-x and gx=x2-x,  x ϵ R . Then the set of all x ϵ R , where the function hx=fogx is increasing, is:
HARD

The graph of the function f(x)=x+18sin(2πx),0x1 is shown below. Define f1(x)=f(x),fn+1(x)=ffnx, for n1 .

Question Image

Which of the following statements are true?

I. There are infinitely many x[0,1] for which limnfn(x)=0

II. There are infinitely many x[0,1] for which limnfn(x)=12

III. There are infinitely many x[0,1] for which limnfn(x)=1

IV. There are infinitely many x[0,1] for which limnfn(x) does not exist .

HARD
Let fx=x+logex-xlogex,x0, . 

   Column 1 contains information about zeros of fx, fx and fx.

   Column 2 contains information about the limiting behaviour of fx, fx and fx at infinity.

   Column 3 contains information about increasing-decreasing nature of fx and fx.
 
Column 1 Column 2 Column 3
(I) fx=0 for some x1, e2 (i) limxfx=0 (P) f is increasing in (0, 1)
(II) fx=0 for some x in 1, e (ii) limxfx=- (Q) f is decreasing in e, e2
(III) fx=0 for some x0, 1 (iii) limxfx=- (R) f is increasing in (0, 1)
(IV) fx=0 for some x1, e (iv) limxfx=0 (S) f is decreasing in e, e2
Which of the following options is the only Correct combination?
HARD
Let fx=xcos-1-sinx,x-π2,π2, then which of the following is true?
MEDIUM
The function f given by f(x)=x3ex is increasing on the interval
MEDIUM
The interval in which the function fx=x3-6x2+9x+10 is increasing, is
HARD
Let fx=1+x1!+x22!+x33!+x44! . The number of real roots of fx=0 is
HARD
The number of points in -,, for which x2-xsinx-cosx=0, is:
HARD
Let R be the set of real numbers and f:RR be given by fx=x-log1+x. We now make the following assertions:

I. There exists a real number A such that fxA for all x

II. There exists a real number B such that fxB for all x.