It is proved that the function y = 3x + 4 is an increasing function on (- ∞, + ∞)

It is proved that the function y = 3x + 4 is an increasing function on (- ∞, + ∞)

Proof: let x1

Prove that the function FX = X3 + 3x is an increasing function on (negative infinity, positive infinity). Please write the steps in detail and use the method of senior one to set x1, X2, thank you

Let x1

Solve the equation. 75 + x = 105 x-23 = 52 x + 38 = 38 can you test it?

30
seventy-five
0

The perimeter of a cube is seven tenths and its area is five tenths

The circumference of a cube is seven tenths
Side length: 7 / 10 △ 4 = 7 / 40
Area: 7x40 / 40 = 49 / 1600
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Given that cos (a + π / 3) = 12 / 13. A is an acute angle, find cosa

A is the acute angle
∴0

Solve the equation: 1 / 2 x + 2 / 5 = 9 / 10
The process of solution
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1 / 2 x = 9 / 10 - 2 / 5
Five tenths x = nine tenths - four tenths
Five tenths x = five tenths
X=1

Proof: the equation AX2 + 2x + 1 = 0 of X has at least one negative root if and only if a is less than or equal to 1
It's necessary and sufficient

Sufficiency: a ≤ 1
When a = 0, the equation becomes 2x + 1 = 0, x = - 1 / 2
When a ≤ 1 and a ≠ 0, the discriminant △≥ 0
4-4a≥0
a≤1
Let two be X1 and X2, respectively
x1+x2=-2/a x1x2=1/a>0
0

The ellipse x2 / A2 + Y2 / B2 = 1 (a > b > 0) is orthogonal to the X axis and A. if there is always P on the ellipse, let OP be perpendicular to AP

Let: O (0,0), a (a, 0), P (acost, bsint), t ≠ 0
OP⊥AP--->(acost,bsint)•(acost-a,bsint) = 0
That is, a & # 178; (COS & # 178; t-cost) + B & # 178; sin & # 178; t-cost
　　　　= a²cos²t-a²cost+(a²-c²)sin²t
　　　　= a²-a²cost-c²(1-cos²t)
　　　　= c²cos²t-a²cost+(a²-c²)=0
--->e²cos²t-cost+(1-e²)=0
--->(cost-1)[e²cost-(1-e²)]=0
∵cost≠1--->-1≤cost=1/e²-1≤1--->0≤1/e²≤2
--->1/2≤e²＜1--->√2/2≤e＜1

Simple calculation 1 + 2 + 3 + 4 + 5 +1000＝

1001*500

How to solve the equation 10x = 3 + X?

10X=3+X
10x-x = 3 + x-x
9X=3
X = 3 △ 9 [divide both sides by 9]
X=1/3