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IB Mathematics: Applications and Interpretation SL · 12.5: Functions · 12.5.6
Functions: exam review Exam review: second paper Answers
Section A: short questions
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- (a) (1.8, 6.05)
- (b) (6.05, 1.8)
- (c) 1.8
- (d) They are inverse functions: the graph of g is the reflection of the graph of f in y = x
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- (a) x = 5 and y = 7
- (b) b = 2, c = 6
- (c) \(f(x)\ne 7\)
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- (a) (0.9, 7.94)
- (b) B is (7.94, 0.9); mirror line y = x
- (c) 0.900
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- (a) t = −5 and S = 720
- (b) The number of subscribers gets close to 720 but never reaches or passes it.
- (c) 480
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- (a) C(30) = 16.70; n = 40
- (b) 0 ≤ n ≤ 80, n a whole number; 3.2 ≤ C ≤ 39.20
- (c) x ≥ −2; g(x) ≥ −1
- (d) −3 ≤ h(x) ≤ 6
Section B: long questions
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- (a) As t increases, k^(−t) tends to 0, so D tends to a; a is the total distance
- (b) b = −25
- (c) k = 1.47
- (d) 5.35 km
- (e) 6.55 hours
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- (a) As t increases, \(k^{-t}\) tends to 0, so D tends to a; a = 40
- (b) b = −40
- (c) k = 1.60
- (d) 9.77 km
- (e) 9 hours
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- (a) y-intercept −48; zeros x = 2 and x = 12; vertex (7, 50); the greatest profit is 50 euros, made at a price of 7 euros
- (b) T = 20; the temperature falls towards but never goes below 20 °C (the temperature of the studio); 89.6 °C
- (c) a = 240; N = 48; as p tends to 0, N grows without limit, so the graph never meets the N-axis (a price of 0 gives no value of N)
- (d) C(0) = 15; n = −6 and C = 5
- (e) Exponential; each value is 3 times the one before
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