If △ ABC vertex coordinates are a (4,2), B (a, - 3), C (- 5, b), and barycenter coordinates (2,1), then a + B=

If △ ABC vertex coordinates are a (4,2), B (a, - 3), C (- 5, b), and barycenter coordinates (2,1), then a + B=

Barycenter coordinates = (4 + a-5 / 3,2-3 + B / 3) = (2,1)
The solution is a = 7, B = 4, a + B = 11

If the coordinates of the three vertices of △ ABC are a (- 5,2), B (1,2), C (3, - 1), then the area of △ ABC is——

A(-5,2)、B（1,2）、C（3,-1）
According to the above points, we know that
The ordinate of AB is the same, that is, the line AB is parallel to the X axis
∴|AB|=|1-(-5)|=6
The distance from C to AB is the difference between the ordinates, i.e
d=|-1-2|=3
∴S△ABC=(1/2)AB*d=9
Have a good time!

If vertex a (- 1.2), B (3.6) and center of gravity g (0.2) of triangle ABC, then the linear equation of AC side is

C(x,y)
0=(-1+3+x)/3
2=(2+6+y)/3
x=2
y=-2
C(2,-2)
A（-1,2）
-2=2k+b
2=-k+b
3k=-4
k=-4/3
b=2/3
y=-4x/3+2/3

Approximate value of π calculated by C + +
1-1/3+1/5-1/7+1/9-1/+...
Do it with while
2. Calculate the factorial of n

//1.
#include
#include
using namespace std;
int main()
{
int k=1;
double m=1,n=0,pi=0;
while(fabs(m)>(1e-6))
{
m=k/(2*n+1);
pi+=m;
k=-k;
++n;
}
cout

How to calculate the approximate value of pie?

Non mathematical proof method: the simple and practical method is to use a ruler to measure and find a standard ring, for example: adhesive tape, you use a knife to cut a small hole in the middle of the adhesive tape, tear it off along both sides of the hole, measure its length as perimeter, and then measure the diameter of the adhesive tape

How to calculate the approximate value of π?

You can change the angle, take a wire, measure its length, then circle it into a circle, measure its diameter, that length is the circumference of the circle, and then divide the circumference by the diameter