mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

6 December

\(p(x)\) is a quadratic with real coefficients. For all real numbers \(x\),
$$x^2+4x+14\leq p(x)\leq 2x^2+8x+18$$
\(p(2)=34\). What is \(p(6)\)?

Between quadratics

Source: Luciano Rila (@DrTrapezio)
\(p(x)\) is a quadratic polynomial with real coefficients. For all real numbers \(x\),
$$x^2-2x+2\leq p(x)\leq 2x^2-4x+3$$
\(p(11)=181\). Find \(p(16)\).

Show answer

Balanced sets

A set of points in the plane is called 'balanced' if for any two points \(A\) and \(B\) in the set, there is another point \(C\) in the set such that \(AC=BC\) (here \(AC\) is the distance between \(A\) and \(C\)).
For all \(n\geq3\), find a balanced set of \(n\) points.

Show answer

Bézier curve

A Bézier curve is created as follows:
1) A set of points \(P_0\), ..., \(P_n\) are chosen (in the example \(n=4\)).
2) A set of points \(Q_0\), ..., \(Q_{n-1}\) are defined by \(Q_i=t P_{i+1}+(1-t) P_i\) (shown in green).
3) A set of points \(R_0\), ..., \(R_{n-2}\) are defined by \(R_i=t Q_{i+1}+(1-t) Q_i\) (shown in blue).
.
.
.
\(n\)) After repeating the process \(n\) times, there will be one point. The Bézier curve is the path traced by this point at \(t\) varies between 0 and 1.

What is the Cartesian equation of the curve formed when:
$$P_0=\left(0,1\right)$$ $$P_1=\left(0,0\right)$$ $$P_2=\left(1,0\right)$$

Show answer & extension

Parabola

On a graph of \(y=x^2\), two lines are drawn at \(x=a\) and \(x=-b\) (for \(a,b>0\). The points where these lines intersect the parabola are connected.
What is the y-coordinate of the point where this line intersects the y-axis?

Show answer & extension

Two lines

Let A and B be two straight lines such that the gradient of A is the y-intercept of B and the y-intercept of A is the gradient of B (the gradient and y-intercept of A are not the same). What are the co-ordinates of the point where the lines meet?

Show answer & extension

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

List of all puzzles

Tags

division lines range number tiling gerrymandering games shape median spheres mean integration colouring trigonometry sport floors area scales people maths factorials books coordinates elections time geometry clocks menace 3d shapes sums 2d shapes folding tube maps addition remainders squares dates digits fractions palindromes cube numbers dominos prime numbers rectangles algebra regular shapes ellipses proportion balancing sequences square numbers triangle numbers star numbers routes chess digital clocks square roots means percentages indices the only crossnumber odd numbers dodecagons coins taxicab geometry volume partitions averages triangles dice irreducible numbers angles factors speed functions advent cryptic clues shapes logic chalkdust crossnumber ave perfect numbers symmetry integers unit fractions sum to infinity complex numbers quadratics probability crossnumber doubling christmas rugby products perimeter graphs pascal's triangle crosswords crossnumbers surds bases money differentiation circles calculus cryptic crossnumbers chocolate probabilty hexagons multiplication polygons grids planes parabolas arrows cards multiples wordplay numbers

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2020