Given any point of the circle C: x2 + y2-4x-14y + 45 = 0, if M (m, n), find the maximum and minimum of n-3 / M + 2. Find out how to calculate the specific point of (x-2)^2+(y-7)^2=8 y=k(x+2)+3 Simultaneously, by substituting equation 2 into equation 1, we get only one solution of the equation about X Why is there only one solution? I don't understand here. How did it come out Why?

The solution transforms the problem of finding the maximum value of n-3 / M + 2 into the problem of simultaneous equations. The idea is to take y = K (x + 2) + 3 as a function system and rotate the straight line continuously to find the maximum value. Because there must be only one for finding the maximum value, no matter the maximum or the minimum, because you think that if there are two, they must be equal, if there is one

If the absolute value of X + 1 and the absolute value of X-2 are the minimum, the value range of X is obtained

×＞0

Given the function f (x) = x + 3, and the sequence {an}, A1 = f (- 1), a (n + 1) = f (an), n belongs to n *, find the general formula of the sequence {an}
If BN = a (n) + 2n, find the sum of the first n terms of the sequence {BN}

a(n+1)=f(an),a(n+1)=an+3
a1=f(-1)=2
an=3n-1
bn=a(n)+2n=5n-1
Sn=5(1+2+3+...+n)-n=5/2*n^2+3/2*n

The probability density of two-dimensional random variable (x, y) is f (x, y) = AE ^ - (x + 2Y), x > 0, Y > 0, others are 0. Calculate the coefficient a and the marginal density function of X, y

For x y simultaneous integration 1 = a ∫ 0 to ∞ e ^ - x DX ∫ 0 to ∞ e ^ - 2Y, Dy solution is a = 2
The marginal probability density f (y) = 2E ^ - 2Y of Y is obtained by integrating X
The marginal probability density f (x) = e ^ - X of X is obtained by integrating y

Find the range of function y = (Sin & sup2; α - 5sin α + 7) / (3-sin α)

Let t = Sina, then there is - 1=

Is there a function that is both odd and even?

Existence
f(x)=0 ,x∈R

How to measure the length of arc on the Geometer's Sketchpad?
How to draw an arc?

The Geometer's Sketchpad has many ways of making arcs
Let's talk about the simplest one
1. Make a circle on the Geometer's Sketchpad
2. Construct two points a and B on the circle
3. Select two points a, B and circle O in turn
4. Click "arc on circle" in "structure"
5. Select circle O and hide it
That's fine
(if the arc is superior, that is, the arc is greater than 180 degrees, select b and a in step 3.)
Measurement of arc length:
1. Select the arc
2. Click "arc length" in "measurement"
That's fine
Last semester, I took the course of Geometer's Sketchpad. I learned it in the first class. Ha ha, fortunately I didn't forget it

In square ABCD, e is the midpoint of AB, BF ⊥ CE is in F, then s △ BFC: s Square ABCD is______ ．

Let the side length of the square ABCD be 2a, ∵ e be the midpoint of AB, ∵ be = a, ∵ CE = be2 + BC2 = 5a, ∵ BF ⊥ CE, ∵ EBC = ∵ BFC = 90 °, ∵ ECB = ∵ BCF, ∵ BCF ∽ EBC. ∵ BC: EC = 2:5. ∵ s △ BFC: s △ EBC = 4:5.