When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Grade (slope) - Wikipedia

    en.wikipedia.org/wiki/Grade_(slope)

    as a percentage, the formula for which is which is equivalent to the tangent of the angle of inclination times 100. In Europe and the U.S. percentage "grade" is the most commonly used figure for describing slopes.

  3. Isotopes of silicon - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_silicon

    Silicon (14 Si) has 25 known isotopes, with mass numbers ranging from 22 to 46. 28 Si (the most abundant isotope, at 92.23%), 29 Si (4.67%), and 30 Si (3.1%) are stable. The longest-lived radioisotope is 32 Si, which is produced by cosmic ray spallation of argon.

  4. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    Diagram showing the cumulative distribution function for the normal distribution with mean (μ) 0 and variance (σ 2) 1. These numerical values "68%, 95%, 99.7%" come from the cumulative distribution function of the normal distribution.

  5. Accuracy and precision - Wikipedia

    en.wikipedia.org/wiki/Accuracy_and_precision

    A reading of 8,000 m, with trailing zeros and no decimal point, is ambiguous; the trailing zeros may or may not be intended as significant figures. To avoid this ambiguity, the number could be represented in scientific notation: 8.0 × 10 3 m indicates that the first zero is significant (hence a margin of 50 m) while 8.000 × 10 3 m indicates ...

  6. Approximations of π - Wikipedia

    en.wikipedia.org/wiki/Approximations_of_π

    The magnitude of such precision (152 decimal places) can be put into context by the fact that the circumference of the largest known object, the observable universe, can be calculated from its diameter (93 billion light-years) to a precision of less than one Planck length (at 1.6162 × 10 −35 meters, the shortest unit of length expected to be ...

  7. Square root of 2 - Wikipedia

    en.wikipedia.org/wiki/Square_root_of_2

    BBP-type formulas are known for π √ 2 and √ 2 ln(1+ √ 2), however. [ 24 ] The number can be represented by an infinite series of Egyptian fractions , with denominators defined by 2 n th terms of a Fibonacci -like recurrence relation a ( n ) = 34 a ( n −1) − a ( n −2), a (0) = 0, a (1) = 6.

  8. Logarithm - Wikipedia

    en.wikipedia.org/wiki/Logarithm

    In chemistry the negative of the decimal logarithm, the decimal cologarithm, is indicated by the letter p. [63] For instance, pH is the decimal cologarithm of the activity of hydronium ions (the form hydrogen ions H + take in water). [64] The activity of hydronium ions in neutral water is 10 −7 mol·L −1, hence a pH of 7. Vinegar typically ...

  9. Uranium - Wikipedia

    en.wikipedia.org/wiki/Uranium

    Main page; Contents; Current events; Random article; About Wikipedia; Contact us