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Edexcel 2017, Q8) A square, with sides of length x cm, is inside a circle. Each vertex of the square is on the circumference of the circle. The area of the circle is 49cm. Work out x.

First we should draw what the question tells us.Draws circle with square inside it
We want to find out some extra information about the circle based on what we have been told.
How can w...

AB
Answered by Alex B. Maths tutor
7418 Views

Why does differentiation work like it does.

Differentiation is about the tangent at a point, from GCSE we have a formula to work out the gradient between two points, in other words, the gradient of the tangent. This means that as the two points get...

LF
Answered by Lucas F. Maths tutor
3214 Views

(a) Express (1+4*sqrt(7))/(5+2*sqrt(7)) in the form a+b*sqrt(7), where a and b are integers. (b) Then solve the equation x*(9*sqrt(5)-2*sqrt(45))=sqrt(80).

(a)   We can ‘get rid of’ a square root in the denominator simply by multiplying by 1 (value of the fraction stays unchanged) in a suitable form. We will take advantage of this formula: (a+b)(a-b)=a^2...

KB
Answered by Kristina B. Maths tutor
7989 Views

Find the equation of the tangent to the curve y=3x^2-7x+5 at the point (2, 3) .

The starting point for a question like this is to differentiate the function - in this case the curve y=3x2 -7x+5 . We calculate that dy/dx=6x-7 . The question tells us that we are interested i...

MS
Answered by Matthew S. Maths tutor
7532 Views

Approximately how long is a double-stranded DNA molecule with a molecular weight of 3x10^9 g/mol? Assume the molecular weight of one nucleotide is 333 g/mol, and that there are 10 base pairs for each turn of the DNA helix equalling 3.4nm in length.

Let's begin by assessing the molecule. If we divide the molecular weight by two, that will give us the weight for one strand of the helix. Knowing that one nucleotide is 333 g/mol, then dividing the wei...

AV
10329 Views

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