Further Functions & Graphs (DP IB Applications & Interpretation (AI))

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  • What is a one-to-one mapping?

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  • What is a one-to-one mapping?

    A one-to-one mapping is a transformation where each input is mapped to exactly one unique output, and no two inputs are mapped to the same output.

  • True or False?

    A many-to-one mapping can be a function.

    True.

    A many-to-one mapping can be a function.

  • What is the vertical line test?

    The vertical line test is a method to determine if a graph represents a function.

    If a graph does represent a function, then any vertical line should intersect with the graph once at most.

  • What is the domain of a function?

    The domain of a function is the set of values that are used as inputs for the function.

  • What is the range of a function?

    The range of a function is the set of values that are given as outputs by the function.

  • What symbol is used to represent the set of all real numbers?

    straight real numbers represents the set of all real numbers (i.e. all the numbers that can be placed on a number line).

  • What does straight rational numbers represent?

    straight rational numbers represents the set of all rational numbers, a over b, where a and b are integers and b not equal to 0.

  • True or False?

    An inverse function reverses the effect of a function.

    True.

    An inverse function reverses the effect of a function.

  • True or False?

    Only a many-to-one function has an inverse function.

    False.

    A many-to-one function does not have an inverse function.

    Only one-to-one functions have inverses.

  • What is the horizontal line test?

    The horizontal line test is a method to determine if a function has an inverse.

    If a function has an inverse, then any horizontal line should intersect with the graph once at most.

  • What is the relationship between the domain of a function and its inverse function?

    The domain of a function becomes the range of its inverse function.

  • State the relationship between the graphs of f open parentheses x close parenthesesand f to the power of negative 1 end exponent open parentheses x close parentheses.

    The graph y equals f to the power of negative 1 end exponent open parentheses x close parentheses is a reflection of the graph y equals f open parentheses x close parentheses in the line y equals x.

    A set of axes showing the graph y = f(x) and it's inverse y = f^-1(x) as a reflection in the line y = x.
  • What are piecewise functions?

    Piecewise functions are functions defined by different equations depending on which interval the input is in.

  • True or False?

    The intervals for individual functions in a piecewise function can overlap.

    False.

    The intervals for individual functions in a piecewise function can not overlap.

  • How do you evaluate a piecewise function for a particular value x equals k?

    To evaluate a piecewise function for x equals k, find which interval includes k and substitute x equals k into the corresponding function.

  • What notation is commonly used to define piecewise functions?

    Piecewise functions are commonly defined using curly brackets with different functions listed for different intervals.

    E.g. f open parentheses x close parentheses equals open curly brackets table row cell 3 x minus 1 end cell cell 0 less than x less or equal than 4 end cell row cell x squared minus 5 end cell cell x greater than 4 end cell end table close

  • How is continuity determined in piecewise functions?

    Continuity in piecewise functions is determined by checking if the function values match at the boundaries between intervals.

    E.g. The piecewise function f open parentheses x close parentheses equals open curly brackets table row cell x plus 8 end cell cell 2 less than x less or equal than 5 end cell row cell 4 x minus 7 end cell cell 5 less than x less or equal than 10 end cell end table close is continuous, because at the boundary between the two intervals, x equals 5, the output is the same: open parentheses 5 close parentheses plus 8 equals 13 and 4 open parentheses 5 close parentheses minus 7 equals 13.

  • How do you determine if a point open parentheses a comma space b close parentheses lies on the graph y equals f open parentheses x close parentheses?

    A point open parentheses a comma space b close parentheses lies on the graph y equals f open parentheses x close parentheses if f open parentheses a close parentheses equals b.

  • What is the difference between the command terms 'draw' and 'sketch' when graphing?

    To sketch: show the general shape of the graph and label key points and axes.

    To draw: use a pencil and ruler to draw the graph to scale, plot points accurately, join points with a smooth curve or a straight line, and label key points and axes.

  • Define asymptote.

    An asymptote is a line which the graph will get closer and closer to but not touch.

  • True or False?

    Most GDC models will automatically plot asymptotes.

    False.

    Most GDC makes/models will not plot or show asymptotes just from inputting a function.

  • How can you use graphs to solve the equation f open parentheses x close parentheses equals a?

    Plot the graphs y equals f open parentheses x close parentheses and y equals a on your GDC, and find the points of intersection.

    The x-coordinates are the solutions of the equation.

  • Define local minimum (maximum).

    A local minimum (maximum) is a point at which the graph reaches the minimum (maximum) value that it takes in the immediate vicinity of the point. The graph may reach lower (higher) values further away from the point.

    It is also called a turning point.

  • True or False?

    A local minimum/maximum is always the global minimum/maximum of a function.

    False.

    A local minimum/maximum is not necessarily the global minimum/maximum (the minimum/maximum of the whole graph).

  • What is the general form of a quadratic function?

    The general form of a quadratic function is f open parentheses x close parentheses equals a x squared plus b x plus c, where a not equal to 0.

    This is not given in your exam formula booklet.

  • How does the equation of quadratic affect the shape of the graph?

    When the equation of a quadratic is given in its general form, f open parentheses x close parentheses equals a x squared plus b x plus c, the coefficient of the x squared term, a, determines the shape of the graph.

    • If a greater than 0, then the equation is positive and the curve is a 'u' shape.

    • If a less than 0, then the equation is negative and the curve is an 'n' shape.

  • What is the vertex of a quadratic function?

    The vertex of a quadratic function, is the turning point of the parabola, lying on the axis of symmetry.

  • What is the formula for the axis of symmetry of a quadratic function?

    The formula for the axis of symmetry of a quadratic function f open parentheses x close parentheses equals a x squared plus b x plus c is x equals negative fraction numerator b over denominator 2 a end fraction

    Where:

    • a is the coefficient of the x squared term for the quadratic in its general form

    • b is the coefficient of the x term for the quadratic in its general form

    This is given in your exam formula booklet.

  • How can you find the y-coordinate of the vertex of a quadratic function?

    Because the vertex of a quadratic function f open parentheses x close parentheses equals a x squared plus b x plus c lies on the axis of symmetry, its x-coordinate is negative fraction numerator b over denominator 2 a end fraction.

    To find the corresponding y-coordinate, you can substitute this x-coordinate back into the equation of the original quadratic function.

  • What is the general form of a cubic function?

    The general form of a cubic function is f open parentheses x close parentheses equals a x cubed plus b x squared plus c x plus d, where a not equal to 0.

    This is not given in your exam formula booklet.

  • How many x-intercepts can a cubic function have?

    The number of x-intercepts that a cubic function can have is 1, 2 or 3.

    It is useful to be able to graph the function to see the number of times that the curve crosses the x-axis.

  • What are the common forms of an exponential function?

    The common forms of an exponential function are

    • f open parentheses x close parentheses equals k a to the power of x plus c,

    • or f open parentheses x close parentheses equals k a to the power of negative x end exponent plus c,

    where a greater than 0.

    Note that an exponential can also be written in terms of the mathematical constant straight e, in the form f open parentheses x close parentheses equals k straight e to the power of r x end exponent plus c.

    These are not given in your exam formula booklet.

  • What part of the equation of an exponential, of the form f open parentheses x close parentheses equals k a to the power of r x end exponent plus c, determines whether its graph is increasing or decreasing?

    To determine whether an exponential of the form f open parentheses x close parentheses equals k a to the power of r x end exponent plus c is increasing or decreasing, look at the coefficient of x (i.e. r) and the value of k.

    • If they have the same sign, then the graph is increasing.

    • If they have different signs, then the graph is decreasing.

  • True or False?

    An exponential function can have up to 2 roots.

    False.

    An exponential function can have a maximum of 1 root.

  • What is the equation of the horizontal asymptote for an exponential function of the form f open parentheses x close parentheses equals k a to the power of x plus c?

    An exponential function of the form f open parentheses x close parentheses equals k a to the power of x plus c has a horizontal asymptote with equation y equals c.

  • What are the coordinates of the y-intercept of an exponential function of the form f open parentheses x close parentheses equals k a to the power of x plus c?

    An exponential function of the form f open parentheses x close parentheses equals k a to the power of x plus c has a y-intercept with coordinates open parentheses 0 comma space k plus c close parentheses.

  • What is the general form of a sinusoidal function, in terms of the sine function?

    The general form of a sinusoidal function in terms of the sine function is f open parentheses x close parentheses equals a sin open parentheses b x close parentheses plus d.

    A sinusoidal function can also be written in terms of the cosine function, f open parentheses x close parentheses equals a cos open parentheses b x close parentheses plus d.

  • What is the principal axis, in the context of a sinusoidal function?

    The principal axis, in the context of a sinusoidal function, is the horizontal line about which a sinusoidal function fluctuates.

    It is halfway between the maximum and minimum values of the curve.

    The equation of the principal axis is y equals d from the general equation f open parentheses x close parentheses equals a sin open parentheses b x close parentheses plus d or f open parentheses x close parentheses equals a cos open parentheses b x close parentheses plus d.

  • True or False?

    The coordinates of the y-intercept for the graph y equals a cos open parentheses b x close parentheses plus d are open parentheses 0 comma space d close parentheses.

    False.

    The coordinates of the y-intercept for the graph y equals a cos open parentheses b x close parentheses plus d are not open parentheses 0 comma space d close parentheses. This is the y-intercept for the graph y equals a sin open parentheses b x close parentheses plus d.

    The coordinates of the y-intercept for the graph y equals a cos open parentheses b x close parentheses plus d are open parentheses 0 comma space a plus d close parentheses. This is because cos open parentheses 0 close parentheses equals 1.

  • Define amplitude, in the context of sinusoidal functions.

    The amplitude of a sinusoidal function is the distance between the principal axis and the maximum value or the distance between the principal axis and the minimum value.

    This is a in the general equation f open parentheses x close parentheses equals a sin open parentheses b x close parentheses plus d or f open parentheses x close parentheses equals a cos open parentheses b x close parentheses plus d.

  • Define period, in the context of a sinusoidal function.

    The period, in the context of a sinusoidal function, is the length of the interval for a complete cycle, e.g. the length of the interval between two maximum points on the graph of a sinusoidal function.

    This is fraction numerator 360 ยบ over denominator b end fraction in the general equation f open parentheses x close parentheses equals a sin open parentheses b x close parentheses plus d or f open parentheses x close parentheses equals a cos open parentheses b x close parentheses plus d.