Monday
December 9, 2013

# Posts by Mgraph

Total # Posts: 317

Math
Let A is the length of a side of the larger square, a - of the smaller square. The length of the smaller side of a rectangle is (A-a)/2, the length of the bigger side is (A-a)/2+a. 4a=2((A-a)/2+(A-a)/2+a) 4a=2A A/a=2/1

find real and complex 0
f(x)=x^3+4x^2-2x^2-8x+2x+8=(x^3+4x^2)- (2x^2+8x)+(2x+8)=x^2(x+4)-2x(x+4)+2(x+4)= (x+4)(x^2-2x+2) x+4=0 => x=-4 or x^2-2x+2=0 => x=1+i or x=1-i

Math
L*W*H=7500 2(L*W+L*H+W*H)=2600 This system has an infinite number of solutions and one of them is: L=30, W=25, H=10

Form a polynomial f(x) from coefficient and it's 0
Because the coefficients of f(x) are REAL, f(x) has zeros: 6i and -6i, 7i and -7i. For example, f(x)=(x-6i)(x+6i)(x-7i)(x+7i)= (x^2+36)(x^2+49)

Statistics
The formula of the conditional probability P(X\Y)=P(XY)/P(Y) a)Y="at least one is a boy" Y=BB+BG+GB, P(Y)=3/4 X=BB If X then Y => XY=X P(XY)=P(X)=1/4 P(X\Y)=(1/4)/(3/4)=1/3 b)Y="the older child is a boy" Y=BB+BG, P(Y)=1/2 X=BB, XY=X, P(XY)=1/4 P(X/Y)=(1/...

Statistics
The formula of the conditional probability P(X\Y)=P(XY)/P(Y) a)Y="at least one is a boy" Y=BB+BG+GB, P(Y)=3/4 X=BB If X then Y => XY=X P(XY)=P(X)=1/4 P(X\Y)=(1/4)/(3/4)=1/3 b)Y="the older child is a boy" Y=BB+BG, P(Y)=1/2 X=BB, XY=X, P(XY)=1/4 P(X/Y)=(1/...

Math

Math