Maths Formulas And Useful Facts, Topic By Topic

Question 1

Formula for Un of an arithmetic sequence?

Answer 1

Un= a + (n-1)d

Question 2

Formula for the sum of an arithmetic sequence?

Answer 2

Sn = n/2 [2a + (n-1)d]

Question 3

Angle at the center of a circle?

Answer 3

The angle at the center of a circle is twice the angle at the circumference subtended by the same arc.

Question 4

Angles in the same segment?

Answer 4

Angles in the same segment of a circle are equal.

Question 5

Cyclic Quadrilateral?

Answer 5

Opposite angles in a cyclic quadrilateral sum to 180

Question 6

Tangent and Radius?

Answer 6

A tangent to a circle is perpendicular to the radius at the point of contact.

Question 7

Angle Subtended by a Diameter?

Answer 7

An angle subtended by a diameter at the circumference is a right angle.

Question 8

Rule for adding algebraic fractions?

Answer 8

A/c+ b/d = ad+bc/bd

Question 9

Rule for subtracting algebraic fractions?

Answer 9

a/b-c/d=ad-bc/bd

Question 10

Rule for multiplying algebraic fractions?

Answer 10

A/b x c/d = ac/bd

Question 11

Formula for the gradient of a line?

Answer 11

M= change in y/change in x

Question 12

Equation of a line?

Answer 12

Y= Mx+ c