What is the radius of the circle x2 + y2 -1=0?

1

Step-by-step explanation:

rewrite x^2 + y^2 -1 = 0 as x^2 + y^2 = 1

the 1 on the right hand side of the equation is equal to the radius squared

1 = r^2

r = 1

radius = 1

Step-by-step explanation:

x^2 + y^2 -1=0

Add 1 to each side

x^2 + y^2 -1+1=0+1

x^2+y^2 = 1

This is written in the form

(x-h)^2 + (y-k)^2 = 1^2  where (h,k) is the center and r is the radius

The center is (0,0) and the radius is 1

i would say c is the best answer, hope it's right!

good luck! =)

cutie~

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;