Somewhat Arbitrary Example Problems:
Esty "Precalculus" (p444 prob.B17):
"When two sound waves are very similar, but not identical, in frequencey, they will reinforce each other at times and nearly cancel each other at other times. For example, if one note is played at 440 cycles per second and a[sic] another note is played at 438 cycles per second, there will be an audible increase and decrease in amplitude twice a second known as a 'beat.' This can be illustrated with a very wide graph of the sum of two sine waves. However, your calculator does not have enough columns of pixels to display such graphs. Near x = 0 the graph of 'sin x + sin (1.01x)' displays reinforcement (graph it and see). Here is the problem: Find, very roughly, the smallest possible c such that this graph displays nearly complete canceling on the interval [c, c + 10]."
AoPS "Prealgebra" (Note this is Prealgebra: p474 challenge prob.12.43):
"The diagonals of a rhombus are perpendicular and the area of a rhombus is half the product of the lengths of its diagonals. Similarly, the diagonals of a kite are perpendicular, and the area of a kite is half the product of its diagonals. Is it true that for any quadrilateral with perpendicular diagonals, the area of the quadrialteral equals half the product of its diagonals? Why or why not? Hints: 45"
Cohen "Precalculus with u.c. trig." (p896 ch11.Test prob.3):
"The distances from the planet Saturn to the Sun at aphelion and at perihelion are 9.5447 AU and 9.5329 AU respectively. Compute the eccentricity of the orbit and the length of the semimajor axis. Round each answer to three decimal places."
David Santos "Precalculus, An Honours Course" (
page 49 Homework prob. 2.8.1)
"Let d > 0 be a real number. Prove that the equation of a parabola with focus at (d,0) and directrix x = -d is x = ##\frac{y^2}{4d}##."
Allendoerfer and Oakley "Principles . . ." 2nd Edition (p245 prob.32)
"Show that it is false that ##∃_{x}## [sin 2x + cos 2x = 4]."
SL Loney "Plane Trigonometry" (p467 prob.13)
"The three sides of a triangle are measured and found to be nearly equal. If the measurements can be wrong one per cent, in excess or defect, prove that the greatest error that can arise in calculating one of the angles is 80' nearly."
I do not have Euler's "Introduction" at hand, so cannot immediately provide an example problem.