Monday, March 11

Learn Analytic Geometry Online


Another name of Analytical  geometry is co-ordinate geometry and it describes as a graph of quadratic equations in the co-ordinate plane. Analytical geometry grew out of need for establishing uniform techniques for solving geometrical problems, the aim being to apply them to study of curves, which are of particular importance in practical problems. In this article we shall discuss the learning analytic geometry ans some example problems

Example Problem 1 to learn analytic geometry online:

Find the equation of the parabola if the curve is open upward, vertex is (− 1, − 2) and the length of the latus rectum is 4.

Solution:

Since it is open upward, the equation is of the form

(x − h)2 = 4a(y − k)

Length of the latus rectum = 4a = 4 and this gives a = 1

The vertex V (h, k) is (− 1, − 2)

The equation of parabola is [x-(-1)]2=4*1 [y-(-2)]

[x+1]2=4[y+2]

Example Problem 2 - Learn analytic geometry online  :

Find the equation of the parabola if

(i) the vertex is (0, 0) and the focus is (− a, 0), a > 0

Solution: (i) From the given data of the parabola is open leftward

The equation of the parabola is of the form

(y − k)2 = − 4a(x − h)

Here, the vertex (h, k) is (0, 0) and VF = a

The required equation is

(y − 0)2 = − 4a (x − 0)

y2 = − 4ax.

Example Problem 3 - learn analytic geometry online :

Find the equation of the parabola if the curve is open rightward, vertex is (2, 1) and passing through point (6,5).

Solution: Since it is open rightward, the equation of the parabola is of the form

(y − k)2 = 4a(x − h)

The vertex V(h, k) is (2, 1)

∴ (y − 1)2 = 4a (x − 2)

But it passes through (6, 5)

(5-1)2 = 4a (6 − 2) -- > 16= 4a * 16

4a= 1 ---- > a = 1/4

The required equation is (y − 1)2 = 1/4 (x − 2)

Example Problem 4 - learn analytic geometry online :

Find the equation of the parabola if the curve is open leftward, vertex is (2, 0) and the distance between the latus rectum and directrix is 2.

Solution: Since it is open leftward, the equation is of the form

(y − k)2 = − 4a(x − h)

The vertex V(h, k) is (2, 0)

The distance between latus rectum and directrix = 2a = 2 giving a = 1 and the equation of the parabola is

(y − 0)2 = − 4(1) (x − 2)

or y2 = − 4(x − 2)

Practice problems- learn analytic geometry online:

1.Find the equation of the parabola whose vertex are (1, 2) and the equation of the directrix x = 3.

The required equation is

(y − 2)2 = 4(2) (x − 1)

(y − 2)2 = 8(x − 1)

2.The separate equations of the asymptotes of the hyperbola 4x2-25y2=100

Answer   :x/5-y/2=0 and x/5+y/2=0

Friday, March 8

Definition to Population Variance


Population variance is defined as the square of the mean deviation value by the total number of data. Population variance is calculated to find the variance in the probability of data.

Formula for finding the

sigma^2 =( sum_(k=1)^n(x_k - mu)^2) / N

Where as

sigma^2 - symbol for population variance

mu - It is the mean of the given data.

N  - Total number of values given in data set.

For finding the population variance we have to find the sample mean. For the take the average for the given values.

 mu = (sum_(K=1) ^n (x_k))/N

This mean value is used in the population variance to find its value.

Population Variance Values - Example Problems:

Population Variance Values - Problem 1:

calculate the population variance for the given data set. 2, 4, 3, 3, 5, 6, 5

Solution:

Mean:  Calculate the mean for the given data

 mu = (sum_(K=1) ^n (x_k))/N

using the above formula find the average for the given values.

 mu = (2+4+3+3+5+6+5)/7

mu = 28/ 7

 mu = 4

Population Variance: Calculate the population variance value from the mean.

sigma^2 =( sum_(k=1)^n(x_k - mu)^2) / N

substitute the mean values to find the deviation values from the given values.

 sigma^2 = ((2-4)^2+(4-4)^2+(3-4)^2+(3-4)^2+(5-4)^2+(6-4)^2+(5-4)^2)/7

sigma^2 = 12/7

sigma^2 = 1.7142857142857

Hence the population variance value is calculated using the mean value.

Algebra is widely used in day to day activities watch out for my forthcoming posts on Differentiation Math and What are Composite Numbers. I am sure they will be helpful.

Population Variance Values - Problem 2:

Find the value for the population variance of the given data set. 367, 378, 365, 366.

Solution:

Mean: Calculate the mean for the given data set using the formula,

 mu = (sum_(K=1) ^n (x_k))/N

Find the mean value that is average of the giave data set

mu = (367+378+365+366)/4

mu = 1476 / 4

mu = 369

Population variance: Calculate the population variance value from the mean.

sigma^2 =( sum_(k=1)^n(x_k - mu)^2) / N

substitute the mean values to find the deviation values from the given values.

sigma^2 =((367-369)^2 + (378-369)^2 + (365 - 369)^2+(366-369)^2) / 4

sigma^2 = 110/4

sigma^2 = 27.5

Hence the population variance value is calculated using the mean value.

Population Variance Values - Problem 3:

Find the value for the population variance of the given data set. 36, 37, 36, 39.

Solution:

Mean: Calculate the mean for the given data set using the formula,

 mu = (sum_(K=1) ^n (x_k))/N

Find the mean value that is average of the giave data set

mu = (36+37+36+39) / 4

mu = 148 / 4

mu = 37

My previous blog post was on Natural Numbers please express your views on the post by commenting.

Population variance: Calculate the population variance value from the mean.

sigma^2 =( sum_(k=1)^n(x_k - mu)^2) / N

substitute the mean values to find the deviation values from the given values.

"sigma^2 = ((36-37)^2 +(37-37)^2+(36-37)^2+(39-37)^2) / 4

sigma^2 = 6/4

sigma^2 = 1.5

Hence the population variance value is calculated using the mean value.

Population Variance Values - Practice Problems:

Find the value for the population variance of the given data set. 45, 47, 49, 43.

Answer: Population Variance = 5

Find the value for the population variance of the given data set. 87, 89, 78, 82, 89.

Answer: Population Variance = 18.8