B. The total because your adding. By adding something you will get the total!
(x²+x)(x²+5x+6) = x^4 + 6x³ + 11x² + 6x + 1 ≥0
f(x) = x^4 + 6x³ + 11x² + 6x + 1
f'(x) = 4x³ + 18x² +22x +6
racines x1 = -0,301 x2 = -1,5 x3 = -2,618
variations
x -2,62 -1,5 -0,3
f'(x) - 0 + 0 - 0 +
f(x) -inf \ 0 / \ 0 /
on voit que cette fonction st toujours positive
The sequence of numbers decrease by 6 each time, so we can write:
f(1) = 5
f(2) = -1
f(3) = -7
f(1) - f(2) = 6
or:
f(2) = f(1) - 6
which means:
f(n + 1) = f(n) - 6
Mean = 0.497 in, SD = 0.003 in
Required diameter ranges between 0.496 in and 0.504 in
Anything other diameter obtained is not acceptable.
That is;
P(x<0.496) and P(x>0.504) are not acceptable.
Now,
P(x<0.496) = P(Z< (0.496-0.497)/0.003)) = P(Z<-0.33)
From Z tables, P(Z<-0.33) = 0.3707
Similarly,
P(x>0.504) = P(Z> (0.504-0.497)/0.003)) = P(Z>2.33)
From Z tables, P(Z>2.33) = 1-0.9901 = 0.0099
Therefore, unacceptable proportion = P(x<0.496)+P(x>0.504) = 0.3707+0.0099 = 0.3806 or 38.06%
