Calculus (Simplified :)) Flashcards
1
Q
- Given equation and a value for x, find the gradient
A
- Differentiate f(x) to get f’(x)
2. Substitue in x value into f’(x) to find the gradient
2
Q
- Given equation and a value for y, find the gradient
A
- Substitute y value into f(x) to find x
- Differentiate f(x) to get f’(x)
- Substitute in x value into f’(x) to find the gradient
3
Q
- Given equation and coordinates of a point, or only the a value, find the equation of a tangent
A
- Substitue x value into f(x) to find y
- Differentiate f(x) to get f’(x)
- Substitute a value into f’(x) to find the gradient of the tangent m
- Substitue into y - y1 = m(x - x1)
- Simplify into y = mx + c
4
Q
- Given equation and gradient, find the coordinates of a point
A
- Differentiate f(x) to get f’(x)
- Make f’(x) = gradient
- Solve to find x value
- Substitue x value into f(x) to find y
5
Q
- Given equation, find turning points and determine nature
A
- Differentiate f(x) to get f’(x)
- Make f’(x) = 0
- Solve to find x value(s)
- Substitue x value(s) into f(x) to find y
- Solve the f’(x) for when f(a number either side of the x value) to ‘check gradient’. If the result for the value is > 0, it is decreasing. If the result is < 0, it is increasing.
6
Q
- Given equation, find where functions are increasing or decreasing
A
- Differentiate f(x) to get f’(x)
- Make f’(x) = 0
- Solve to find x values
- Solve the f’(x) for when f(a number either side of the x values) to ‘check gradient’. If the result for the value is > 0, it is decreasing. If the result is < 0, it is increasing.
- Write as a domain with middle value determining whether it is increasing or decreasing where (lower x value) < x < (higher x value)
7
Q
- Rates of change - Given the value of x
A
- Differentiate f(x) to get f’(x)
- Substitue x value into f’(x) to find y
- Write as, when x is (__), y is (increasing/decreasing) at (__).
8
Q
- Rates of change - Given the value of y
A
- Substitute y value into f(x) to find x
- Differentiate f(x) to get f’(x)
- Substitue x value into f’(x) to find y
- Write as, when y is (__) and x is (__), the y is
(increasing/decreasing) at (__).
9
Q
- Rates of change - Given the value of dy/dx (rate)
A
- Differentiate f(x) to get f’(x)
- Make f’(x) = rate
- Solve to find x value
- Write as, y is (increasing/decreasing) at (rate) when x is (__).
10
Q
- Optimisation
A
Note - At maximum and minimum points, gradient = 0
- Differentiate f(x) to get f’(x)
- Make f’(x) = 0
- Solve to find x value
- Substitue x value into f(x) to find y
11
Q
- Optimisation with related variables
A
- Draw a diagram
- Identify what needs to be optimized and write an equation
- Write an equation which relates x and y
- Substitute for y
- Differentiate f(x) to get f’(x)
- Make f’(x) = 0
- Solve to find x value
- Substitue x value into f(x) to find y
- Test solution then answer question
12
Q
- Antidifferentiation
A
- Add 1 to the power
- Divide the constant by the new power
- Add +c to the end of the equation
13
Q
- Antidifferentiation - Given a point on the original curve, calculate c
A
- Antidifferentiate f’(x) to get f(x)
- Substitue x and y values into f(x) to find c
- Rewrite f(x) with xy variables and value of c
14
Q
- Antidifferentiation - Given a pair of values in a rate of change problem, calculate c
A
Note - The pair of values will be different variables (eg. How deep was the water after 10 minutes? - The variables are depth and time)
- Antidifferentiate f’(x) to get f(x)
- Substitue initial ‘x’ and ‘y’ values into f(x) to find c
- Substitue final x or y value into f(x)
- Solve to find the other x or y value
15
Q
- Antidifferentiation - Given a graph of the gradient function and point it passes through, sketch the original curve
A
- Write the equation for the line
- Antidifferentiate f’(x) to get f(x)
- Substitute coordinate of point into f(x) to find c
- Calculate the minimum/maximum value by solving f(x) for when x = the x-axis intercept
- Draw parabola with the turning point in line with x-axis intercept and curving upwards if gradient of line is positive, or curving downwards if gradient of line is negative