Grade 10 Functions — Advanced Practice

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Question 1 of 28: g(x) = 3f(x) compared to f(x) is:

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Answer key for parents & teachers (28 questions)
  1. g(x) = 3f(x) compared to f(x) is:Vertically stretched by factor 3. a·f(x) with |a| > 1 vertically stretches the graph by factor a. All y-values are multiplied by 3.
  2. g(x) = f(2x) compared to f(x) is:Horizontally compressed by factor 2. f(bx) with |b| > 1 horizontally COMPRESSES by factor b. Points come closer together horizontally.
  3. g(x) = (1/2)f(x) compared to f(x) is:Vertically compressed by factor 2. a·f(x) with 0 < a < 1 vertically compresses the graph. All y-values are halved.
  4. g(x) = √(x + 4) − 1 is f(x) = √x shifted:Left 4, down 1. f(x+4) → left 4 (inside, + means left). −1 outside → down 1.
  5. g(x) = |x − 2| + 3 is f(x) = |x| shifted:Right 2, up 3. f(x−2) → right 2. +3 outside → up 3.
  6. The point (3, 5) on f(x) maps to which point on f(x) + 7?(3, 12). Vertical shift up 7: y-coordinate increases by 7. New point: (3, 5+7) = (3, 12).
  7. Which parameter in g(x) = a·f(b(x − h)) + k produces vertical stretches?a. Parameter a (multiplied outside) produces vertical stretches (|a| > 1) or compressions (|a| < 1). It also reflects when a < 0.
  8. Horizontal transformations (inside f) work in the _____ direction of the algebraic sign.Opposite. This is the key rule: f(x − h) shifts RIGHT (opposite of minus), f(x + h) shifts LEFT (opposite of plus). Inside transformations are counterintuitive.
  9. g(x) = f(x) × 0.25 compared to f(x) is:Vertically compressed by factor 4. a = 0.25 < 1 → vertical compression. All y-values are multiplied by 0.25 (become 1/4 as tall).
  10. g(x) = √(−x) compared to f(x) = √x is:Reflected over the y-axis. f(−x) reflects the graph over the y-axis. √(−x) is defined for x ≤ 0 (left side), a mirror of √x.
  11. The vertex of g(x) = (x − 3)² + 5 is at:(3, 5). g(x) = f(x−3) + 5 shifts the vertex of f(x) = x² (at origin) right 3 and up 5. Vertex: (3, 5).
  12. The graph of f⁻¹ is the reflection of f over the line:y = x. The inverse function's graph is the reflection of the original over the line y = x. This swaps all (a, b) pairs to (b, a).
  13. f(x) = x³. What is f⁻¹(x)?x^(1/3) = ∛x. y = x³ → x = y³ → y = x^(1/3) = ∛x. The cube root undoes cubing.
  14. If f(f⁻¹(x)) = x, then applying f⁻¹ then f returns:x (the original input). f(f⁻¹(x)) = x — applying inverse then original returns the original input x.
  15. f(x) = 5 is a constant function. Does it have an inverse function?No — it fails the horizontal line test. f(x) = 5 maps every x to 5 — it is many-to-one, failing the horizontal line test. It has no inverse function.
  16. f(x) = x², g(x) = 3. Find (f ∘ g)(x).9. (f ∘ g)(x) = f(g(x)) = f(3) = 3² = 9. This is a constant function.
  17. f(x) = 4x + 7. What is f⁻¹(11)?1. f⁻¹(x) = (x − 7)/4. f⁻¹(11) = (11 − 7)/4 = 4/4 = 1. Verify: f(1) = 4+7 = 11 ✓.
  18. If f and g are inverse functions, the composition graph f(g(x)) = x represents which line?y = x. f(g(x)) = x is the identity function, represented by the line y = x.
  19. Composition of f followed by g is written as:g ∘ f. (g ∘ f)(x) = g(f(x)) — f is applied first. The notation g ∘ f reads "g of f" and applies f first.
  20. f(x) = x + 4, g(x) = 2x. Find (g ∘ f)(x).2(x + 4) = 2x + 8. (g ∘ f)(x) = g(f(x)) = g(x + 4) = 2(x + 4) = 2x + 8.
  21. A piecewise function is CONTINUOUS if:At each boundary point, both pieces give the same value. Continuity requires that at each boundary/transition point, the function values from both sides match — no "jumps."
  22. f(x) = {2x + 1 if x < 2; 7 if x = 2; x² − 1 if x > 2}. Is f continuous at x = 2?No — 2(2)+1=5 ≠ 7 at x = 2. Left limit: 2(2)+1 = 5. Right limit: 4−1 = 3. f(2) = 7. All three differ → NOT continuous at x = 2.
  23. Which real-world situation can be modeled by a piecewise function?A shipping rate that changes based on package weight. Shipping rates use different formulas for different weight ranges — a perfect piecewise model. Tax brackets work the same way.
  24. The graph of a piecewise function can have:Multiple distinct pieces that may or may not connect. A piecewise function's graph has separate pieces over different x-intervals. They may connect (continuous) or not (discontinuous).
  25. What does an "open circle" on a piecewise graph indicate?The endpoint is NOT included (the domain condition is strict, < or >). An open circle at a point means that point is NOT included in the piece — a strict inequality (< or >) at that boundary.
  26. What does a "closed circle" on a piecewise graph indicate?The endpoint IS included (the domain uses ≤ or ≥). A closed (filled) circle indicates the endpoint IS included — a non-strict inequality (≤ or ≥) at that boundary.
  27. For the 3-piece function above, what is f(−3) + f(0) + f(2)?All three are correct (9). f(−3): x<−1, use −x = 3. f(0): −1≤x<2, use x+2 = 2. f(2): x≥2, use 4. Sum = 3+2+4 = 9.
  28. Which mathematical concept is modeled by f(x) = ⌊x⌋ (the floor function)?A piecewise constant (step) function. The floor function ⌊x⌋ equals the greatest integer ≤ x. It creates a step pattern — constant on each interval, with jumps at integers.