Recent content by bobthebanana

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    Undergrad Simple least squares regression problem. Am I doing anything wrongly?

    Least squares regression of Y on A-D based on sample size of 506 [FONT="Courier New"] Y = 11.08 - 0.954*A - 0.134*B + 0.255*C - 0.052*D s.errs (0.32) (0.117) (0.043) (0.019) (0.006) R^2 = 0.581 problem A. Test null that coefficient on D is equal to 0 d = coefficient on...
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    Equivalent resistors/capacitors etc. tricky problem

    Homework Statement Find equivalent capacitance between terminalsHomework Equations C_eq = C_1 + C_2 for parallel C_eq = 1/((1/C_1) + (1/C_2))The Attempt at a Solution I can't tell what's in parallel and what's in series. That conductor in the center is throwing me off. Any help por favor? You...
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    Undergrad How can i express this Infinite series without a summation symbol?

    yea number 3
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    Undergrad How can i express this Infinite series without a summation symbol?

    (1/2) + (2/4) + ... + (n/(2^n)) = sum i=1 to i=infinity of (i/(2^i))?i know how to express the sum of just 1/(2^i), but not the above thanks for the help!
    • bobthebanana
    • Thread
    • Infinite Infinite series Series Summation Symbol
    • Replies: 9
    • Forum: Calculus
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    Graduate How Do You Calculate Ray and Ellipsoid Intersections?

    So I have an array p(t) = e + td, where e is the start position, t is some parameter, and d is the direction of the ray For a sphere with center c and radius R, the vector form equation is (p-c).(p-c)-R^2=0 This can be algebraically manipulated into: t = (-d.(e-c) +- sqrt((d.(e-c))^2 -...
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    Find the mysterious function that converts an 8 digit num to a 10 digit num

    This isn't a homework question. You guys are smart so I was wondering if you could somehow figure out the mysterious function f based on a few examples: f(26134914) = 2085386485 f(26288902) = 2085920342 f(26289423) = 2094236422 f(26356300) = 2086136115 What is "f" doing to convert that 8 digit...
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    High School Simple problem 3x = 1 (mod 16), find all possible values of x mod 16

    Well is there a systematic way to solve a problem like this? what if it were mod 2008
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    High School : simple problem 3x = 1 (mod 16), find all possible values of x mod 16

    URGENT: simple problem... 3x = 1 (mod 16), find all possible values of x mod 16 simple problem... 3x = 1 (mod 16), find all possible values of x mod 16 so this is what I've come to: 3x = 1 + 16k, where k is any integer i'm stuck though, any help? thanks
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    High School Simple problem 3x = 1 (mod 16), find all possible values of x mod 16

    simple problem... 3x = 1 (mod 16), find all possible values of x mod 16 so this is what I've come to: 3x = 1 + 16k, where k is any integer i'm stuck though, any help? thanks
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    Undergrad How can I calculate the radius of an ellipse at a specific angle?

    so from center... is it: (ab)/((b^2cos^2t+a^2sin^2t)^(3/2)) or (ab)/((b^2cos^2t+a^2sin^2t)^(1/2))?
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    Undergrad How can I calculate the radius of an ellipse at a specific angle?

    yes i need the radius from the center as opposed to one of the foci... what is the formula? I'm not sure how to convert to polar coordinates x = rcos(theta) y = rsin(theta) and plug those values into that equation and solve for "r"? or am i doing something wrongly?
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    Undergrad How can I calculate the radius of an ellipse at a specific angle?

    wikipedia says it's (1 - e^2) as opposed to (1 - e) in that equation nrqed. Who's right?
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    Undergrad How can I calculate the radius of an ellipse at a specific angle?

    given the major axis length, minor axis length, at the given angle THETA. what's the formula?
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    DYNAMICS: SPINNING CONE WITH MASS TIME SENSITIVE (30 mins)

    k got it thanks
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    DYNAMICS: SPINNING CONE WITH MASS TIME SENSITIVE (30 mins)

    gravity, normal, friction? and normal is different because it's spinning?