Answer is: option3
\( \int_0^a [f(x) + 3]\, dx + \int_a^b [-3 - f(x)]\, dx \)Solution:
Given:
- The curve \( y = f(x) \) intersects the line \( y = -3 \) at points \( (0, -3) \), \( (a, -3) \), and \( (b, -3) \).
- Between \( x = 0 \) and \( x = a \), \( f(x) > -3 \).
- Between \( x = a \) and \( x = b \), \( -3 > f(x) \).
Step-by-Step Solution:
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Area between \( x = 0 \) and \( x = a \):
- Here, \( f(x) \) is above \( y = -3 \), so the height of the region is \( f(x) - (-3) = f(x) + 3 \).
- The area is:
\( \int_0^a [f(x) - (-3)]\, dx = \int_0^a [f(x) + 3]\, dx \)
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Area between \( x = a \) and \( x = b \):
- Here, \( y = -3 \) is above \( f(x) \), so the height of the region is \( -3 - f(x) \).
- The area is:
\( \int_a^b [-3 - f(x)]\, dx \)
- Total Area:
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The sum of the two areas is:
\( \int_0^a [f(x) + 3]\, dx + \int_a^b [-3 - f(x)]\, dx \)
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The sum of the two areas is:
Matching with Options:
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Option (C) matches exactly with the derived expression:
\( \int_0^a [f(x) + 3]\, dx + \int_a^b [-3 - f(x)]\, dx \)