Variable Definition and 1000 Threads

A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either:

Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.
Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it.Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.

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  1. ChrisVer

    A Bin Width for Overlay Plots of Data + Estimation

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  2. W

    Change a variable to transform a series into a power series

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  3. K

    I Deriving expression as a function of another variable

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  4. Jehannum

    I Rearranging equation with more than variable instance

    This question is no doubt absurdly simple to many here, but the answer will help me immensely. Say that: c = a ^ 4 Then it's simple to rearrange for a: a = c ^ 0.25 But what if there is more than one term, for example: c = a ^ 4 + a ^ 3 Is it possible to rearrange this to the form: a =...
  5. T

    I Isolating a complex-valued variable

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  6. H

    I How Should Derivatives in Multivariable Chain Rules Be Notated?

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  7. baby_1

    Using Cauchy's Tip for Changing Integral Variable Inconsistencies

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  8. T

    MHB Does the Limit of the Function Approach Zero as (x, y) Tends to (0,0)?

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  9. T

    MHB Evaluating limit of 2 variable function

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  10. G

    B Understanding Correlations in Non-Realism: The Role of Extra Variables?

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  11. anorlunda

    A Conjugate variable clarification

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  12. T

    I Change of variable (2nd order ODE)

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  13. I

    MATLAB Transforming part of matlab code to Fortran90

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  14. I

    Normal approximation to Poisson random variable

    Homework Statement Suppose that the number of asbestos particles in a sam- ple of 1 squared centimeter of dust is a Poisson random variable with a mean of 1000. What is the probability that 10 squared cen- timeters of dust contains more than 10,000 particles? Homework Equations E(aX+b) =...
  15. N

    Double integrals with variable upper limit

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  16. Einstein's Cat

    B Exploring Variable Speed of Light Theories

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  17. F

    Exploring the Number of Pi Groups in Dimensional Analysis

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  18. P

    A Approximation for volatility of random variable

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  19. R

    Mass of an annulus with variable mass density

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  20. O

    I Concrete contrast between local and nonlocal hidden variable

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  21. RubiksMelia

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  22. T

    I Change of variable - partial derivative

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  23. S

    MLE of Bivariate Vector Random Variable: Proof & Explanation

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  24. W

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  25. evinda

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  26. F

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  27. N

    Help with variable mass on a slope question

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  28. terryds

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  29. W

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  30. Telemachus

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  31. I

    Quadratic with variable buried in sqrt?

    Homework Statement 0 = -250*(sqrt(x^2+1)-0.8)^2 + 98.1*x + 59.05 Homework EquationsThe Attempt at a Solution I can't figure out how to solve this equation! After expanding the squared term, I still end up with a sqrt(x^2+1) and I can't figure out how to perform a substitution or something to...
  32. Kirito123

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  33. S

    I Integration of 1 variable in 2 different ways.

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  34. S

    A reusable variable: still good to define in the scope that uses it?

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  35. F

    Choosing repeating variable in pi Buckingham theorem

    Homework Statement why we can't form the pi group by using repeating variable of (μ, ρ , v) or (D, v , μ ) ? http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/dimension/node9.html http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Section5/dimensional_analysis.htm...
  36. Edison Bias

    I Integral problems with polar coordinates and variable substitution

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  37. abdulsulo

    Fortran Taking 1/7 power of a variable

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  38. H

    B Recast a differential equation with a change of variable

    I obtained an extra factor of ##\frac{1}{l^2}## in the first term on the LHS of (3.34). From (3.33), LHS ##=u^2\frac{d}{d\theta}(\frac{u^2}{m}\frac{du}{d\theta}\frac{dr}{du})-\frac{l^2u^3}{m}## ##=u^2\frac{d}{d\theta}(-\frac{1}{m}\frac{du}{d\theta})-\frac{l^2u^3}{m}##...
  39. topsquark

    MHB PHP Static Variables: Why Doesn't It Reset?

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  40. avikarto

    Fortran Modern variable precision and integer multipliers

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  41. D

    MHB Question regarding a probability mass function of a random variable

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  42. D

    MHB Continuous random variable question

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  43. D

    MHB Consider the following probability mass function of a random variable x

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  44. Narasoma

    I Hidden Variable Interpretation

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  45. I

    I Random variable and probability

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  46. F

    MHB Understanding Uniform Random Variables: Comparing $X$ and $Y = 1-X$

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  47. U

    Variable Voltage Transformer for Wind Turbine Battery Charging?

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  48. N

    C/C++ C++: Printing output based on variable value

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  49. K

    Standardization of a random variable

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  50. F

    MHB Random Variable over probability space

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