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Well, edit : thanks for Randy's answer, nevertheless he is not correct Sum [ (x_i)^2 ] = sum [ b^2 x_i^2 = b^2 sum x_i^2. expresses : VarX = Sum [ (x_i)^2 ] which is only correct if E(X) = 0...

2 Answers · Science & Mathematics · 19/03/2016

...32π / 3 ) * ( 8 - 4√3 ) ..... Ans Note. tan^2 15° = 7 - 4√3

**pf**: By the formula : tan ( β / 2 ) = ± √ [ ( 1 - cos β ) / ( 1 + cos β ) ] ...1 Answers · Science & Mathematics · 27/02/2016

3t + 4s = 20 A = (1/2) * t * sqrt(t^2 - (t/2)^2) + s^2 A = (1/2) * t * t * sqrt(1 - 1/4) + s^2 A = (1/2) * t^2 * sqrt(3)/2 + s^2 A = (sqrt(3) / 4) * t^2 + s^2 3t + 4s = 20 3t = 20 - 4s t = (4/3) * (5 - s) A = (sqrt(3)/4) * (4/3)^2 * (5 - s)^2 + s^2 A = (sqrt(3)/4) * (16/9) * (25 - 10s + s^2) + s^2 A = (16...

2 Answers · Science & Mathematics · 17/01/2016

...focus, and Q(-3, y) be the projection of P onto the given directrix.

**PF**= 2PQ √[(x - 3)² + y²] = 2|x + 3| (x - 3)² + y²...2 Answers · Science & Mathematics · 09/12/2015

This is a linear decrease, since the decrease amount is constant (100). So, after t years, the number

**pf**people will be P = 9000 - 100t2 Answers · Science & Mathematics · 09/11/2015

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**pf**=m&fir=1nQ8XVbDJ3SanM%253A%252CvisLaZH2khC3pM...2 Answers · Science & Mathematics · 29/10/2015

... P(x,y) is a point on the parabola, then d(P,L) =

**PF**1/2 - y = √ [ x^2 + ( y + 1/2 )^2 ] 1/4 - y + y^2 = x^2 + ( y + 1/2 )^2 1/4...1 Answers · Science & Mathematics · 16/09/2015

... = 2.28*10^9 lbs/km². Multiply this by the surface area

**pf**516*10^6 km² and you get 1.19*10^19 lbs. If we assume that...1 Answers · Science & Mathematics · 05/05/2015

... of BC & CA respectively. Drop a perpendicular

**PF**on AB. To prove AF = FB. BD = DC. ...1 Answers · Science & Mathematics · 23/04/2015

I(t) = V/R * (1-e^-Rt/L) = 60/12 * (1 - e^-3t) = 5 as t-> infinity Don't normally answer anonymous questions because I prefer to help people thoughtful enough to be grateful which is becoming very rare these days.

1 Answers · Science & Mathematics · 12/04/2015