mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

An integral

Source: Alex Bolton (inspired by Book Proofs blog)
What is
$$\int_0^{\frac\pi2}\frac1{1+\tan^a(x)}\,dx?$$

Show hint


Show answer & extension

Find them all

Find all continuous positive functions, \(f\) on \([0,1]\) such that:
$$\int_0^1 f(x) dx=1\\ \mathrm{and }\int_0^1 xf(x) dx=\alpha\\ \mathrm{and }\int_0^1 x^2f(x) dx=\alpha^2$$

Show answer & extension

Integrals

$$\int_0^1 1 dx = 1$$
Find \(a_1\) such that:
$$\int_0^{a_1} x dx = 1$$
Find \(a_2\) such that:
$$\int_0^{a_2} x^2 dx = 1$$
Find \(a_n\) such that (for \(n>0\)):
$$\int_0^{a_n} x^n dx = 1$$

Show answer & extension

Double derivative

What is
$$\frac{d}{dy}\left(\frac{dy}{dx}\right)$$
when:
(i) \(y=x\)
(ii) \(y=x^2\)
(iii) \(y=x^3\)
(iv) \(y=x^n\)
(v) \(y=e^x\)
(vi) \(y=\sin(x)\)?

Show answer & extension

Differentiate this

$$f(x)=e^{x^{ \frac{\ln{\left(\ln{x}\right)}}{ \ln{x}}} }$$
Find \(f'(x)\).

Show answer

x to the power of x again

Let \(y=x^{x^{x^{x^{...}}}}\) [\(x\) to the power of (\(x\) to the power of (\(x\) to the power of (\(x\) to the power of ...))) with an infinite number of \(x\)s]. What is \(\frac{dy}{dx}\)?

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

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

Archive

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