If A-B = 6 and ab = 7, find the sum of squares of a + B and a + B

If A-B = 6 and ab = 7, find the sum of squares of a + B and a + B

Square of a + square of B: square (a-b) to: A & # 178; - 2Ab + B & # 178; = 36, then a & # 178; - 2Ab + B & # 178; + 2Ab = A & # 178; + B & # 178; = 36 + 14 = 50
a+b：(a+b)^2=(a-b)^2+4ab
(a+b)^2=6^2+4*7
(a+b)^2=36+28
(a+b)^2=64
a+b=±8

If A-B = 5, ab = 3,2, find the sum of a square + b square and (a + b) square

a-b=5
(a-b)^2=25
a^2-2ab+b^2=25
a^2+b^2=25+2ab=25+2*(3/2)=25+3=28
(a + b) square
=a^2+2ab+b^2
=a^2+b^2+2ab
=28+2*(3/2)
=28+3
=31

2 ^ 2-1 ^ 2 = 3 3 ^ 2-2 ^ 2 = 5 4 ^ 2-3 ^ 2 = 7 calculate the value of 1 + 3 + 5 + 7 +... + 2005 + 2007 according to the above rule

1=1^2
3=2^2-1^2
5=3^2-2^2
……
2007=1004^2-1003^2
So 1 + 3 + 5 + 7 +... + 2005 + 2007
=1^2+2^2-1^2+3^2-2^2+…… +1004^2-1003^2
=1004^2-1^2
=1008015

Let's know the set a = {x | a ≤ x ≤ a + 3}, B = {x | x2-4x-5 > 0}. If a ∩ B = ￠ then the value range of a is

Let's first look at B. when x is not equal to 0, x > 5 or X5 or X

5 [x + 7.5] = 40 solution equation 2.5x + 7 * 2.5 = 40 solution equation
5 [x + 7.5] = 40 solution equation 2.5x + 7 * 2.5 = 40 solution equation

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Left:
X+7.5=40÷5
X+7.5=8
x =0.5
Right:
2.5X+17.5-17.5=40-17.5
2.5X=22.5
x =9
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The bottom of a parallelogram is 12.5, the height is 6, and the diagonal is 10
I can't figure it out. I always think it's wrong. Some people say that if it's 12.5 * 6 divided by 2 = 7.5, then the perimeter is 12.5 + 12.5 + 7.5 + 7.5 = 50
Wrong. Wrong. It's perimeter

Square of 10 - square of 6 = square of 8
12.5-8=4.5
4.5 * 4.5 + 6 * 6 = 56.25 = 7.5 square
Then the other edge is 7.5
The perimeter is 12.5 * 2 + 7.5 * 2 = 40

Proportional solution equation 12: x = 3.5:4.2

12:X=3.5：4.2
3.5X=12*4.2
3.5X=50.4
X=50.4/3.5
X=14.4

The tangent equation of curve y = ln (x + 2) at point P (- 1,0) is______ ．

Find out the derivative function, y ′ = 1 x + 2, the slope of the tangent is k = y ′| x = - 1 = 1, it can be obtained from the point oblique formula, the tangent equation of the curve y = ln (x + 2) at the point (- 1,0) is y-0 = x - (- 1), that is, X-Y + 1 = 0, so the answer is: X-Y + 1 = 0

When y is any positive integer, the value of algebraic formula 2 (Y-1) is less than that of 10 + 4 (Y-3)

Because 10 + 4 (Y-3) - 2 (Y-1) = 2Y, for any positive integer y, the result is greater than 0, that is to say, the former is greater than the latter when y takes any positive integer

If sin (cosx) * cos (SiNx) > 0, find the range of X

∵ 1 ≥ SiNx ≥ - 1, cosx = - cosx, - π / 2 ≥ SiNx ≥ π / 2 ∵ 1 ≥ cos (SiNx) > 0 ∵ if sin (cosx) * cos (SiNx) > 0, as long as sin (cosx) > 0 ∵ when - π / 2 ≤ x ≤ 0, SiNx ≤ 0 and ∵ 1 ≥ cosx ≥ - 1 ∵ when cosx > 0, sin (cosx) > 0, sin (cosx) * cos (SiNx