Q34 / 54 · JEE Advanced 2017 (Paper 1) · Mathematics
Let
Column 1 contains information about zeros of , and
Column 2 contains information about the limiting behaviour of , and at infinity.
Column 3 contains information about increasing-decreasing nature of and Column 1 Column 2 Column 3 (I) for some (i) (P) is increasing in (II) for some (ii) (Q) is decreasing in (III) for some (iii) (R) is increasing in (IV) for some (iv) (S) is decreasing in
Column 1 contains information about zeros of , and
Column 2 contains information about the limiting behaviour of , and at infinity.
Column 3 contains information about increasing-decreasing nature of and
| Column 1 | Column 2 | Column 3 |
| (I) for some | (i) | (P) is increasing in |
| (II) for some | (ii) | (Q) is decreasing in |
| (III) for some | (iii) | (R) is increasing in |
| (IV) for some | (iv) | (S) is decreasing in |
- A(III) (iv) (P)
- B(I) (ii) (R)
- Correct answerC(II) (iii) (S)
- D(IV) (i) (S)
Solution
In Column 1,
(I) so true
(II) so true
(III) is always positive for so it cannot be zero. So (III) is false.
(IV) Is false
In Column 2
As
(i) is false (ii) is true
,so (iii) is true.
, so (iv) is true.
(P) is positive in ,so true.
(Q) ,for in ,so true.
As therefore, R is false, S is true.
Alternate Solution:
at where
concave down

Hence, the correct answer is option: 'C'.