Search our library of A Level questions

Top answers

All subjects

A Level

A circle has equation: (x - 2)^2 + (y - 2)^2 = 16. It intersects the y-axis (y > 0) at point P and the x-axis (x < 0) at point Q. Find the equation of the line connecting P and Q and of the line perpendicular to PQ passing through the circle's centre.

(x - 2)² + (y - 2)² = 16 x = 0 --> 4 + (y - 2)² = 16 --> y - 2 = ±2sqrt{2} --> y = 2 ± 2sqrt{2} --> P(0,2 + 2sqrt{2})y = 0 --> (x - 2)² + 4 = 16 ...

Answered by • Maths tutor

3365 Views

Using the factor theorem, factorise x^4 - 3x^3 - 3x^2 + 11x - 6

Well the question states that it wants you to use the factor theorem so it would be a good idea to write down the factor theorem to remind ourselves."A polynomial f(x) has a factor (x - a) if and onl...

Answered by Kester G. • Maths tutor

4702 Views

(a) Explain what is meant by monopoly and, using a diagram, explain why a monopoly may have lower average costs of production than a firm in perfect competition. [10]

· Definition and examples of different types of monopoly.I.e. pure, natural, and local monopolies.High barriers to entry&exit / price-makers.· Definition of perfect competition.Many buye...

Answered by Ethan S. • Economics tutor

3165 Views

How do vaccinations work? Relating to humoral immunity and the secondary immune response.

The body has both humoral and cell mediated immunity. A vaccination involves injecting a patient with inert (Inactivated) or dead material from a pathogen, be that a bacterium or a virus. Once injected in...

Answered by Sophie J. • Biology tutor

3328 Views

Describe two ethical issues related to Milgram's study of obedience

Deception was used in order to carry out the experiment. Participants were unaware of the confederates in the experiment and that they would always be assigned as a teacher and the confederate would...

Answered by Dristi M. • Psychology tutor

19466 Views