If the absolute value of the slope of a straight line is known to be equal to one, the inclination angle of the straight line can be calculated Why do you know y = + - x from the title?

If the absolute value of the slope of a straight line is known to be equal to one, the inclination angle of the straight line can be calculated Why do you know y = + - x from the title?

45 degrees or 135 degrees
Y = + - x
Then the absolute value of Tan a = 1
A = 45 degrees or 135 degrees

If the parabola y ^ 2 = x has two symmetrical points about the straight line when the straight line passes (1,1), the value range of the slope k of the straight line is obtained
Let Y-1 = K (x-1)
simultaneous equation
y-1=k(x-1)
y^2=x
so what?

Let two points on the parabola y ^ 2 = x be (x1, Y1) (X2, Y2), then the distance between these two points and the straight line is equal, and an equation is obtained
(1,1) is the point on the straight line and parabola y ^ 2 = x, so the straight line and parabola y ^ 2 = x intersect to get an equation

Let m (2, - 5) n (- 3,2) and the line L pass through the point P (1,1) with an intersection point, then the value range of the slope k of the line can be obtained

Trace m (2, - 3), n (- 3, - 2) and connect Mn in rectangular coordinate system
The line L passing through the point P (1,1) intersects the line segment Mn in three cases
When k > 0, the slope of the line L passing through point n (- 3, - 2) and P (1,1) is the smallest
That is, K ≥ (1 + 2) / (1 + 3) = 3 / 4
When k ＜ 0, the slope of line L passing through M (2, - 3), P (1,1) is the largest
That is, K ≤ (1 + 3) / (1-2) = - 4
When the line L is parallel to the Y axis, the line L intersects the segment Mn, but the slope k does not exist
Therefore, the slope k of the line L is in the range of K ≥ 3 / 4, or K

Given a (- radical 3, - 1), B (0,2), then the inclination angle of the line AB is?

Tangent of inclination angle of straight line = [2 - (- 1)] / (0-3) = - 1
So AB tilt angle = 135 degrees
Haven't you learned? The tangent of the inclination angle of a line is called the slope of the line
The slope of a straight line passing through two points = the difference between ordinates / abscissa (such as the algorithm in the above question)

As shown in the figure, in the rectangular ABCD, DC = 5 cm, there is a point E on DC, and △ AED is folded along the straight line AE, and the pilot d just falls on the edge of BC. Let this point be f. if the area of △ ABF is 30 cm, then the area of △ AED is___ .

SABF=1/2AB*BF
If BF = 12, ab = 5, AF = 13, that is, ad = 13 can be obtained
So FC = 1
EF+EC=5
EF^2=1+EC^2
EF = 13 / 5, that is, de = 13 / 5
SAED=1/2AD*DE=1/2*13*13/5=169/10=16.9

As shown in the figure, in the rectangular ABCD, DC = 5cm, there is a point E on DC. Fold △ AED along the line AE, so that point d just falls on the edge of BC. Let this point be f. if the area of △ ABF is 30cm2, calculate the area of folded △ AED

From the symmetry of folding, ad = AF, de = EF. From s △ ABF = 12bf, ab = 30, ab = 5, BF = 12. In RT △ ABF, from Pythagorean theorem, AF = AB2 + BF2 = 13. So ad = 13. Let de = x, then EC = 5-x, EF = x, FC = 1. In RT △ ECF, EC2 + FC2 = ef2, that is, (5-x) 2 + 12 = x2

As shown in the figure, if AE = 3.5, AF = 2.8, ∠ EAF = 30 ° respectively, then ab=______ ，AD=______ ．

Because AF ⊥ BC, ad ∥ BC, so AF ⊥ ad, so ∠ DAE + ∠ EAF = 90 ° so ∠ DAE = 60 ° so ∠ d = 30 ° in RT △ ade, ad = 2ae = 7, ab = 5.6

If the two sides of a triangle are 2 and 6, and the third side is even, the perimeter of the triangle is______ ．

According to the trilateral relationship of a triangle, we can get 6-2 < x < 6 + 2, that is 4 < x < 8. If the length of the third side is even, then x = 6. If the perimeter of the triangle is 2 + 6 + 6 = 14, then the perimeter of the triangle is 14. So the answer is: 14

If the lengths of two sides of a triangle are 2 and 7 respectively, and the third side is even, find the perimeter of the triangle

If the sum of the two sides is greater than the third side, the difference is less than the third side, and the third side is even, then it can only be between 7-2 = 5 and 7 + 2 = 9, which may be 6 or 8, so the perimeter is 15 or 17

If the lengths of the two sides of a triangle are 2 and 7, and the perimeter is even, the length of the third side is?

The sum of the lengths of the two sides of the triangle is greater than the third side, and the absolute value of the difference between the lengths of the two sides is less than the third side. Therefore, we can calculate that the range of the third side should be between 5 and 9, and 2 + 7 is odd, so 5 and 9 should also be an odd number to meet the requirement of even perimeter, so we take 7