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Match List-I with List-II

List-IList-II
FunctionIncreasing on the interval
(A) f(x)=−x2−2x+1f(x) = -x^2 - 2x + 1(I) (−∞,−1)(-\infty, -1)
(B) f(x)=x2+1f(x) = x^2 + 1(II) (1,∞)(1, \infty)
(C) f(x)=x2−2x+3f(x) = x^2 - 2x + 3(III) (−∞,0)(-\infty, 0)
(D) f(x)=−x2f(x) = -x^2(IV) (0,∞)(0, \infty)

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 1

For any function, it's increasing where its derivative is positive (f′(x)>0f'(x) > 0).


(A) f(x)=−x2−2x+1f(x) = -x^2 - 2x + 1

Find the derivative:

f′(x)=−2x−2f'(x) = -2x - 2

f′(x)=−2(x+1)f'(x) = -2(x + 1)

For the function to be increasing:

−2(x+1)>0-2(x + 1) > 0

x+1<0x + 1 < 0

x<−1x < -1

Increasing on (−∞,−1)(-\infty, -1) → Matches (I)


(B) f(x)=x2+1f(x) = x^2 + 1

Find the derivative:

f′(x)=2xf'(x) = 2x

For the function to be increasing:

2x>02x > 0

x>0x > 0

Increasing on (0,∞)(0, \infty) → Matches (IV)


(C) f(x)=x2−2x+3f(x) = x^2 - 2x + 3

Find the derivative:

f′(x)=2x−2f'(x) = 2x - 2

f′(x)=2(x−1)f'(x) = 2(x - 1)

For the function to be increasing:

2(x−1)>02(x - 1) > 0

x−1>0x - 1 > 0

x>1x > 1

Increasing on (1,∞)(1, \infty) → Matches (II)


(D) f(x)=−x2f(x) = -x^2

Find the derivative:

f′(x)=−2xf'(x) = -2x

For the function to be increasing:

−2x>0-2x > 0

x<0x < 0

Increasing on (−∞,0)(-\infty, 0) → Matches (III)


Final matching:

(A) → (I)

(B) → (IV)

(C) → (II)

(D) → (III)

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