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- What are quadratic equations? Using examples
A quadratic equation is an polynomial , second degree.
A quadratic equation can have 2 different solutions or 1 solutions or no solutions.
We can use a scientific calculator, Casio fx991EX to solve a quadratic equation .
Move to Menu and bring down the arrow key to the rectangle A, click on = and click on 2 , Polynomial,click on 2 for degree, as it is a quadratic equation and enter the value of a,b,c as quoted.
Press equal and the solutions x1 and x 2 will appear on the screen or only x for a single solution.
x^2 +2x+1=0 , solution x=-1
x^2 -5x+6=0 , solution x1=2 and x2= 3
If you do not use a calculator , you need to apply the formula for the discriminant of the equation , Discriminant = b^2 -4ac , where a,b,c, are the values in the quadratic formula and for the solutions .
If the Discrimiant is >0 , we have 2 solutions x=( -b+-square root( b^2-4ac))/2a
If the Discriminant =0 , we have 1 solution x -b/2a
If the Discriminant is<0 , no solutions .
- What are Circle Theorems? A guide with examples
- The angle is a semi circle is 90 degree. Any right angle triangle can be found inside a circle where the diameter is the triangle hypotenus.
- Opposites angles of a cyclic quadrilateral add up to 180 degree.
- Angles in the same segment are equal.
- The angle at the centre of the circle is twice the angle on the circumference.
- The perpendicular from a chord to the centre of the circle bisects the chord.
- The angle between the tangent and a chord is equal to the angle in the alternate segment.- Alternate segment .theorem.
- Calculating the interior and exterior angles of a polygon
- In a regular polygon all the sides are equal and all the angles are equal .
- If a regular polygon has n sides , then each exterior angle is 360/n.
- We can use the fact the angles on a straight line add up to 180 degree to work
- out the size of the interior angles.
- For a polygon with n sides,
- Sum of the interior angles=180 x (n-2)
- Sum of the exterior angles = 360/n
- What are the laws of indices for multiplication and division? A guide with examples
- Indices include square roots, cube roots and powers.
- When you multiply two same number, you add the indices .
- a^m xa^n= a^m+n
- a^m/a^n= a^m-n
- When you divide two same number , you subtract the indices.
- 3^2 x 3 ^5 = 3 ^2+5= 3^8
- 4^9/4^2= 4^7
- Power of zero = 1 and power of 1= to itself.
- 8^0=1 and 8^1= 8
Negative power: a^-n= 1/a^n
a^-1= 1/a
- Here are the topics you need to know for GCSE maths
- Number: Factors and primes, indice, fractions , decimals, standard form, surds,....
- Algebra: Factorising, linear equation, arithmetic sequences, quadratic equations, simultaneous equations,inequalities, equation of a circle, functions, inverse functions, velocity time graphs.....
- Ratio and Proportion : Ratio , proportion, percentage change, speed, density.
- Geometry and measures: Angles and properties, trigonometry, angle in polygons, circles, surface area , bearings, the sin and cosine rules, Pythagoras, vectors.....
- Probability and Statistics :Mean , median and mode, interquartile range, box plots, probability, tree diagrams.....
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- Best textbooks for A-Level Maths
- Revise Edexcel AS Mathematics, C1,C2, M1,S1 D1
- A level year 2, Mathematics , Edexcel .