MEI OCR A Level formulas to remember. All Exam Questions and Correct
Answers | Graded A+ | 2025/2026 Update|
Roots of ax^2 + bx + c = 0 -
When there is a positive discriminate... - there are 2 real roots
When the discriminate is zero... - there is 1 repeated real root
When there is a negative discriminate... - there are imaginary roots.
The modulus of x is when... - the value of x is only shown as positive.
If the modulus of x is less than a... - then x is more than -a and less that +a
The notation nCr means... - from r chose n, used with pascals triangle.
a^m x a^n = - a^m+n
a^m / a^n = - a^m-n
Anything to the power of 0 will equal - 1
a^-m = - 1/a^m
a^1/n = - the nth root of a
, (a^m)^n = - a^mn
A gradient of a line can be found using... - m=(y2-y1)/(x2-x1)
The length between two points on a line can be found using... - square root[ (x2-x1)^2 +
(y2-y1) ^2]
The equation of a line can be found using... - y2-y1=m(x2-x1)
The midpoint of two points can be found using - [(x2-x1)/2 , (y2-y1)/2]
The gradient of a line perpendicular to another is... - the negative reciprocal
A circle has an equation of... - (x-a)^2 + (y-b)^2 = r^2, where (a,b) is the centre.
logx+logy= - log(xy)
logx-logy= - log(x/y)
log(x^n)= - nlogx
log(nth root x)= - 1/n logx
-log x= - log 1/x
A log with a base a, loga = - 1
Answers | Graded A+ | 2025/2026 Update|
Roots of ax^2 + bx + c = 0 -
When there is a positive discriminate... - there are 2 real roots
When the discriminate is zero... - there is 1 repeated real root
When there is a negative discriminate... - there are imaginary roots.
The modulus of x is when... - the value of x is only shown as positive.
If the modulus of x is less than a... - then x is more than -a and less that +a
The notation nCr means... - from r chose n, used with pascals triangle.
a^m x a^n = - a^m+n
a^m / a^n = - a^m-n
Anything to the power of 0 will equal - 1
a^-m = - 1/a^m
a^1/n = - the nth root of a
, (a^m)^n = - a^mn
A gradient of a line can be found using... - m=(y2-y1)/(x2-x1)
The length between two points on a line can be found using... - square root[ (x2-x1)^2 +
(y2-y1) ^2]
The equation of a line can be found using... - y2-y1=m(x2-x1)
The midpoint of two points can be found using - [(x2-x1)/2 , (y2-y1)/2]
The gradient of a line perpendicular to another is... - the negative reciprocal
A circle has an equation of... - (x-a)^2 + (y-b)^2 = r^2, where (a,b) is the centre.
logx+logy= - log(xy)
logx-logy= - log(x/y)
log(x^n)= - nlogx
log(nth root x)= - 1/n logx
-log x= - log 1/x
A log with a base a, loga = - 1
