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For the graph of y = 4 + 3x − x², determine a) The coordinates of the point where the curve cuts the y-axis b) The coordinates of the point where the curve cuts the x-axis c) The coordinates of any minimum or maximum points d) Hence sketch the graph of y = 4 + 3x − x²
ScanSolve AI Answer
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| Point | x | y |
|---|---|---|
| x-intercept | −1 | 0 |
| y-intercept | 0 | 4 |
| Maximum | 1.5 | 6.25 |
| x-intercept | 4 | 0 |
Step-by-step solution
10 stepsHere are the solutions to Question One.
The given curve is . This is a quadratic equation, representing a parabola that opens downwards (because the coefficient of is negative).
Question 1a) The coordinates of the point where the curve cuts the y-axis.
The curve cuts the y-axis when .
Substitute into the equation.
State the coordinates.
The coordinates where the curve cuts the y-axis are .
Question 1b) The coordinates of the point where the curve cuts the x-axis.
The curve cuts the x-axis when .
Set the equation to 0.
Rearrange the quadratic equation to standard form :
Factor the quadratic equation.
We need two numbers that multiply to -4 and add to -3. These numbers are -4 and 1.
Solve for .
State the coordinates.
The coordinates where the curve cuts the x-axis are .
Question 1c) The coordinates of any minimum or maximum points.
Find the derivative of the function with respect to .
Set the derivative to zero to find the x-coordinate of the stationary point.
Substitute the x-coordinate back into the original equation to find the y-coordinate.
To add these, find a common denominator (4):
Determine if it's a minimum or maximum point.
The second derivative . Since , the point is a maximum.
The coordinates of the maximum point are .Question 1d) Hence sketch the graph of .
Using the points calculated:
- y-intercept:
- x-intercepts: and
- Maximum point:
The graph is a parabola opening downwards, passing through these points.
^ y | 6.25 . (1.5, 6.25) Max | 4 . (0, 4) | | | -1 ---.-------.-------.-----> x | 0 4 |(A textual representation of the sketch is provided above. For a precise visual sketch, plot these points on a coordinate plane and draw a smooth parabolic curve through them, opening downwards.)
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