In a triangle, the lines of high CE and BD on the sides of AB and AC intersect at point O. if the triangle ABC is not a right triangle and the angle a = n degrees, the degree of the angle BOC is calculated

In a triangle, the lines of high CE and BD on the sides of AB and AC intersect at point O. if the triangle ABC is not a right triangle and the angle a = n degrees, the degree of the angle BOC is calculated

It's 180-n
The angle BOE = angle COD and the angle EOD = angle BOC can be obtained when the angle is 180 degrees
We also know that a quadrangle is 360 degrees
Available angle BOC = angle EOD = 360-90-90-n = 180-n
180 degrees - n degrees = (180-n) degrees
That is, aeod is a quadrilateral internal angle and 360 degrees
If the independent variable value range of function y = - 2x + 3 is - 1 less than x less than or equal to 2, then the value range of function y is -______ .
-1 less than x less than or equal to 2? Is there a problem with this condition!
If (- 1 < x ≤ 2)
If the independent variable value range of function y = - 2x + 3 is - 1 less than x less than or equal to 2, then the value range of function y is (1 < y ≤ 7)
The angle bisectors OB and OC of ∠ ABC, ACD intersect at point O to find the relationship between ∠ BOC and ∠ a
∠A=180-∠ABC-∠ACB
∠BOC=180-∠OBC-∠OCB
∵∠OCB=∠ACB+∠ACO=∠ACB+1/2(180-∠ACB)=90+1/2∠ACB
And ∵ ∠ OBC = 1 / 2 ∠ ABC
∴∠BOC=180-（90+1/2∠ACB）-1/2∠ABC=90-1/2∠ACB-1/2∠ABC=1/2∠A
In the function y = x + 1 / 3x-4, the value range of the independent variable x is?
A: X ≠ 4 / 3 B: X ≠ 1 C: X ＜ 4 / 3 or X ≠ - 1 D: X ＞ 4 / 3
The reasons for choosing a are as follows:
y=（x+1）/（3x-4）
=1/3*（x-4/3+7/3）/（x-4/3）
=1/3+（7/3）/（x-4/3）
That is, X ≠ 4 / 3,
So choose a
As shown in the figure, point O is a point within △ ABC, and ob bisects ∠ ABC, OC bisects ∠ ACB, ∠ BOC = 130 °, then the degree of ∠ A is______ .
According to the sum of internal angles of triangle is 180 °∠ 1 + ∠ 3 = 180 ° - 130 ° = 50 °, OB bisects ∠ ABC, OC bisects ∠ ACB, so ∠ ABC + ∠ ACB = 50 °× 2 = 100 °; in △ ABC, ∠ a = 180 ° - 100 ° = 80 °; answer: the degree of ∠ A is 80 °. So the answer is 80 °
The value range of the independent variable in the function y = 1-3x / X is ()
If the symmetrical point P 'of point P (a, b) about X axis is in the third quadrant, then the image of the line y = ax + B does not pass through the () quadrant
If the line y = 2x + B intersects with the line y = - 2 / 5x + 3 and Y axis at the same point, then B = (),
Denominator 1-3x ≠ 0
So x ≠ 1 / 3
If p 'is in the third quadrant, then p is in the second quadrant
So A0
So the line is only the third quadrant
Y-axis then x = 0
So x = 0
y=0+b=0+3
B=3
Point O is a point on the ABC plane of an equilateral triangle, ∠ AOB: ∠ BOC: ∠ AOC = 3:4:5, calculate OA: OB: OC
With ob as the edge, make equilateral triangle OBD outside BC, connect cdab = BC, ABO = 60-cbo = CBD, Bo = BD, so ABO congruent CBD Ao = CD, OB = OD, ODB = 60, ODC = 90-60 = 30, Doc = 120-60 = 60ocd = 180-30-60 = 90oa: OB: OC = CD: od: OC = root 3:2
When y = 3x + 1, y = x-3 / X-1, the value of independent variable x is in what range, the function analytic formula is meaningful
You first need to know the definition of each function
1、 When the function analysis is integral, the range of independent variable is all real numbers
2、 When the analytic expression of function is fraction, the value range of independent variable is all real numbers whose denominator is not zero
3、 When the analytic expression of a function is a quadratic radical, the root number is all nonnegative real numbers
4、 When the base of zero power or negative integer power contains an independent variable, the base is not zero
5、 The value range of independent variable is determined by the change range of function value
6、 In practical problems, the range of independent variables should make the problem meaningful
Then the equations are listed according to the conditions,
When the molecule is not zero
Functions are meaningful
therefore
X-3≠0
X≠3
O is in the regular triangle ABC, the angle AOB = 110 degrees, the angle BOC = 135 degrees. Can we form a triangle with OA, ob, OC as sides? Yes, we can find the degree of its internal angle; no, we can explain the reason
Instead, remember OA = a, OB = B, 0C = C, as shown in the figure: rotate triangle AOB 60 degrees to ACD position, then OA = ad = a, OB = CD = B connect OD, then: angle oad = angle OAC + angle CAD = angle OAC + angle Bao = 60 degrees, so: Triangle oad is equilateral triangle, so: od = a in triangle
When the function y equals 3x minus 6 / 6 x, the value range of the independent variable x is
X is not equal to 2