She draws the graph shown on the grid.
Trigonometric & exp. Graphs — Notes & Worked Examples Show / Hide
Explanation:
Both y = sin x and y = cos x oscillate between −1 and 1 with a period of 360°: sin x starts at (0°, 0), peaks at (90°, 1), crosses at (180°, 0), reaches (270°, −1), and returns to (360°, 0); cos x starts at (0°, 1) and is symmetrical about x = 180°. y = tan x has period 180° with vertical asymptotes at 90° and 270°.
Exponential graphs y = abx (b > 0) always pass through (0, a) because b0 = 1, and have the x-axis (y = 0) as a horizontal asymptote. When b > 1 the graph shows exponential growth; when 0 < b < 1 it shows exponential decay.
Example 1: Solve sin x = −0.5 for 0° ≤ x ≤ 360°.
Solution:
Example 2: The curve y = abx passes through (0, 5) and (3, 40). Find a and b.
Solution:
She draws the graph shown on the grid.
The graph passes through the point with coordinates (-1, 1.5)
Worked Solution & Answer
⇒ 1/k = 3/2
⇒ k = 2/3. A1
Worked Solution & Answer
passes through (0, 0), (180, 0), (360, 0) with period 180°. A1
Give the coordinates of any points of intersection with the axes.
Worked Solution & Answer
approaches y = 0 as x → –∞ and increases rapidly for x > 0. A1
Worked Solution & Answer
For x > 0, 3x > 2x, so the curve is steeper and lies above y = 2x
For x < 0, 3x < 2x, so the curve is closer to the x-axis and lies below y = 2x. A1
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Worked Solution & Answer
At t = 1, d = 6 ⇒ 3 × b¹ = 6 ⇒ b = 2. A1
\sin x° = 0.3 for -180 ≤ x ≤ 180 [2 marks]
\sin(x + 20)° = 0 for -180 ≤ x ≤ 180 [1 mark]
Worked Solution & Answer
14 (b) Draw the graph of y = 2x for x from –1 to 3. [2 marks]
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Worked Solution & Answer
2¹ = 2
2³ = 8 A1
Worked Solution & Answer
(ii) the point Q [2 marks]
Show the coordinates of any points of intersection with the coordinate axes. [2 marks]