Science & Mathematics

The hardest problem on the hardest test

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Works through the famously hard Putnam problem about the probability that a random tetrahedron in a sphere contains its centre, by first solving the 2D version.

7. Solving Ax = 0: Pivot Variables, Special Solutions

869K views

MIT 18.06, lecture 7: Solving Ax = 0 by finding pivot variables and the special solutions that span the nullspace.

Lecture 10: Clicker Bonanza and Dirac Notation

140K views

MIT 8.04, lecture 10: Dirac bra-ket notation, worked through with concept questions.

Lecture 11: Dispersion of the Gaussian and the Finite Well

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MIT 8.04, lecture 11: Spreading of a Gaussian wave packet and bound states of the finite well.

Ejemplo de longitud de arco por integración

A 7-minute math video from KhanAcademyEspañol covering Longitud del arco de una curva y superficie, the section of OpenStax Calculus Volume 1 (Spanish edition) it is paired with.

7.27 | Using energy considerations and assuming negligible air resistance, show that a rock thrown

A 10-minute physics worked example from The Glaser Tutoring Company, solving exercise 7.27 of OpenStax College Physics 2e step by step.

Expansión en fracciones parciales

A 12-minute math video from KhanAcademyEspañol covering Fracciones parciales, the section of OpenStax Precalculus 2e (Spanish edition) it is paired with.

Ejemplo: encontrando la matriz inversa

A 9-minute math video from KhanAcademyEspañol covering Resolver sistemas con inversas, the section of OpenStax Precalculus 2e (Spanish edition) it is paired with.

15.17a | Calculate the concentration of all solute species: TlCl(s) in 0.025 M TlNO3

A 15-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 15.17a of OpenStax Chemistry 2e step by step.

2.35 | Consider a grey squirrel falling out of a tree to the ground. (a) If we ignore air resistance

A 11-minute physics worked example from The Glaser Tutoring Company, solving exercise 2.35 of OpenStax College Physics 2e step by step.

7.49 | Write the Lewis structures for the following, and include resonance structures where

A 11-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 7.49 of OpenStax Chemistry 2e step by step.

Límites al infinito | Ej. 1 → 4 #julioprofe

A 13-minute math video from julioprofe covering Límites al infinito y asíntotas, the section of OpenStax Calculus Volume 1 (Spanish edition) it is paired with.

3.63c | Find the molarity: .35 L of a 0.350-M solution of H3PO4 is diluted to a final volume of 4.00

A 4-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 3.63c of OpenStax Chemistry 2e step by step.

11.3 | When KNO3 is dissolved in water, the resulting solution is significantly colder than the

A 13-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 11.3 of OpenStax Chemistry 2e step by step.

11.18 | The aqueous humor in a person’s eye is exerting a force of 0.300 N on the 1.10-cm2 area of

A 4-minute physics worked example from The Glaser Tutoring Company, solving exercise 11.18 of OpenStax College Physics 2e step by step.

27.61 | A telescope can be used to enlarge the diameter of a laser beam and limit diffraction

A 6-minute physics worked example from The Glaser Tutoring Company, solving exercise 27.61 of OpenStax College Physics 2e step by step.

13.25b | Convert the values of Kc to values of Kp: H2(g) + I2(g) ⇌ 2HI(g) Kc = 50.2 at 448 °C

A 6-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 13.25b of OpenStax Chemistry 2e step by step.

1.91 | Calculate these volumes. (a) What is the volume of 25 g iodine, density = 4.93 g/cm3?

A 7-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 1.91 of OpenStax Chemistry 2e step by step.

13.53 | What is the atmospheric pressure on top of Mt. Everest on a day when water boils there at a

A 2-minute physics worked example from The Glaser Tutoring Company, solving exercise 13.53 of OpenStax College Physics 2e step by step.

11.28 | Verify that work input equals work output for a hydraulic system assuming no losses to

A 7-minute physics worked example from The Glaser Tutoring Company, solving exercise 11.28 of OpenStax College Physics 2e step by step.

7.41 | A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen by

A 11-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 7.41 of OpenStax Chemistry 2e step by step.

15.76b | Identify the Lewis acid and the Lewis base: B(OH)3 + OH− → B(OH)4−

A 7-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 15.76b of OpenStax Chemistry 2e step by step.

8.17a | Analysis of a compound indicates that it contains 77.55% Xe and 22.45% F by mass. (a) What

A 7-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 8.17a of OpenStax Chemistry 2e step by step.

11.9 | Explain why the ions Na+ and Cl− are strongly solvated in water but not in hexane, a solvent

A 9-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 11.9 of OpenStax Chemistry 2e step by step.

18.9 | How many coulombs of positive charge are there in 4.00 kg of plutonium, given its atomic mass

A 4-minute physics worked example from The Glaser Tutoring Company, solving exercise 18.9 of OpenStax College Physics 2e step by step.

27.65 | The planet Pluto and its Moon Charon are separated by 19,600 km. Neglecting atmospheric

A 3-minute physics worked example from The Glaser Tutoring Company, solving exercise 27.65 of OpenStax College Physics 2e step by step.

8.47 | A 3000-kg cannon is mounted so that it can recoil only in the horizontal direction.

A 8-minute physics worked example from The Glaser Tutoring Company, solving exercise 8.47 of OpenStax College Physics 2e step by step.

4.43b | Find the number of moles and the mass of oxygen formed by the decomposition of 1.252 g of

A 12-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 4.43b of OpenStax Chemistry 2e step by step.

9.5 | Repeat the seesaw problem in Example 9.1 with the center of mass of the seesaw 0.160 m to the

A 11-minute physics worked example from The Glaser Tutoring Company, solving exercise 9.5 of OpenStax College Physics 2e step by step.

4.17b | Determine the oxidation states of the elements in Al(OH)3

A 5-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 4.17b of OpenStax Chemistry 2e step by step.

6.13 | RGB color television and computer displays use cathode ray tubes that produce colors by

A 13-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 6.13 of OpenStax Chemistry 2e step by step.

2.13 | Conversations with astronauts on the lunar surface were characterized by a kind of echo in

A 6-minute physics worked example from The Glaser Tutoring Company, solving exercise 2.13 of OpenStax College Physics 2e step by step.

14.42 | Calculate the rate of heat conduction through a double-paned window that has a 1.50-m2 area

A 20-minute physics worked example from The Glaser Tutoring Company, solving exercise 14.42 of OpenStax College Physics 2e step by step.

Parábola - Ej. 1

A 8-minute math video from julioprofe covering La parábola, the section of OpenStax Precalculus 2e (Spanish edition) it is paired with.

Ejemplo de un ejercicio del método de Euler

A 5-minute math video from KhanAcademyEspañol covering Campos de direcciones y métodos numéricos, the section of OpenStax Calculus Volume 2 (Spanish edition) it is paired with.

9.7 | Canadian tire pressure gauges are marked in units of kilopascals. What reading on such a gauge

A 3-minute chemistry worked example from The Glaser Tutoring Company, solving exercise 9.7 of OpenStax Chemistry 2e step by step.