
We can find the gradient of PM and of PN. The gradient at P should lie between these two values. We can also find the gradient of MN which may give an even more accurate estimate.
This approach is called "differentiation from first principles"
This method may not be be part of your examination, but is here to give you a chance to see what lies behind the methods you use.
Summary/Background


Software/Applets used on this page
Glossary
calculus
the study of change; a major branch of mathematics that includes the study of limits, derivatives, rates of change, gradient, integrals, area, summation, and infinite series. Historically, it has been referred to as "the calculus of infinitesimals", or "infinitesimal calculus".
There are widespread applications in science, economics, and engineering.
There are widespread applications in science, economics, and engineering.
curvature
how fast a curve is changing direction at a given point
differentiation
The process of finding a derivative.
gradient
The slope of a line; the angle of its inclination to the horizontal.
integral
the anti-derivative
integration
the process of finding an integral, the reverse process to differentiation.
magnitude
A measure of the size of a mathematical object
newton
the unit of force
product rule
The rule for differentiating products:
(uv)' = uv' + u'v
(uv)' = uv' + u'v
rule
A method for connecting one value with another.
solve
To find the answer or solution to a problem.
straight
The type of line produced by a linear equation.
union
The union of two sets A and B is the set containing all the elements of A and B.
This question appears in the following syllabi:
Syllabus | Module | Section | Topic | Exam Year |
---|---|---|---|---|
AP Calculus AB (USA) | 3 | Differentiation | First principles | - |
AP Calculus BC (USA) | 3 | Differentiation | First principles | - |
AQA A-Level (UK - Pre-2017) | C1 | Differentiation | First principles | - |
AQA AS Maths 2017 | Pure Maths | Differentiation | From First Principles | - |
AQA AS/A2 Maths 2017 | Pure Maths | Differentiation | From First Principles | - |
CBSE XI (India) | Calculus | Limits and Derivatives | Definition of a derivative | - |
CCEA A-Level (NI) | C1 | Differentiation | First principles | - |
CIE A-Level (UK) | P1 | Differentiation | First principles | - |
Edexcel A-Level (UK - Pre-2017) | C1 | Differentiation | First principles | - |
Edexcel AS Maths 2017 | Pure Maths | Differentiation | From First Principles | - |
Edexcel AS/A2 Maths 2017 | Pure Maths | Differentiation | From First Principles | - |
I.B. Higher Level | 6 | Differentiation | First principles | - |
I.B. Standard Level | 6 | Differentiation | First principles | - |
Methods (UK) | M8 | Differentiation | First principles | - |
I.B. (MSSL) | 7 | Differentiation | First principles | - |
OCR A-Level (UK - Pre-2017) | C1 | Differentiation | First principles | - |
OCR AS Maths 2017 | Pure Maths | Differentiation Basics | From First Principles | - |
OCR MEI AS Maths 2017 | Pure Maths | Differentiation Basics | From First Principles | - |
OCR-MEI A-Level (UK - Pre-2017) | C2 | Differentiation | First principles | - |
Pre-U A-Level (UK) | 4 | Differentiation | First principles | - |
Scottish Advanced Highers | M1 | Differentiation | First principles | - |
Scottish (Highers + Advanced) | HM1 | Differentiation | First principles | - |
Scottish Highers | M1 | Differentiation | First principles | - |
Universal (all site questions) | D | Differentiation | First principles | - |
WJEC A-Level (Wales) | C1 | Differentiation | First principles | - |