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A circle C with centre at the point (2, –1) passes through the point A at (4, –5).....

(a) Find an equation for the circle C. Before tackling a question like this it is always a good idea to draw a rough sketch of all the information that's given to you. The general equation of a circle is x 2...
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Answered by Brodie W. • Maths tutor
18884 Views

Express 3 cos θ + 4 sin θ in the form R cos(θ – α), where R and α are constants, R > 0 and 0 < α < 90°.

To find the value of R, use Pythagoras's Theorem using the coeffecients of cos θ and sin θ. The correct answer should be R=5. Expand the expression R cos(θ – α). Equate the expanded expression with 3 cos θ +...
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Answered by Anahita G. • Maths tutor
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The cost of 5 calculators is £35. Work out the cost of 8 of these calculators.

If the cost of 5 calculators is equal to £35, then we can use division to figure out how much one calculator costs. If we divide 35 by 5 we get the number 7. This means that one of the calculators is going t...
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Answered by Danielle S. • Maths tutor
5191 Views

What are surds and how does multiplying them work?

A surd is an irrational number which cannot be expressed as a fraction or a recurring number. E.g. root 2 = 1.4142135…. and it continues (but it does NOT repeat like a recurring fraction though) . E.g. pi wo...
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Answered by Febi S. • Maths tutor
9462 Views

How do I use the product rule for differentiation?

The product rule is a rule for differentiating products of expressions, i.e. 2 expressions multiplied together. The rule is: if y=A B, then dy/dx=A dB/dx +B*dA/dx. This can be remembered as &quot;Write down ...
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Answered by Thomas E. • Maths tutor
9726 Views