Answer:
Step-by-step explanation:
We khow that the equation of a circle is written this way :
(x-a)²+(y-b)²=r² where (x,y) are the coordinates of the cercle's points and (a,b) the coordinates of the cercle's center and r the radius .
Our task is to khow the values of a and b :
- We khow that the center is lying on the line 3x+2y=16⇒ 2y=-3x+16⇒ y=
x+8 - We khow that the points P and Q are two points in the cercle
- Let Ω be the center of this cercle
- we can notice that : PΩ AND QΩ are both equal to the radius ⇒ PΩ=QΩ= r
- So let's write the expression of this distance using vectors KHOWING THAT Ω(a,b)
- Vector PΩ(a-4,b-6) and Vector QΩ(a-8,b-2)
- PΩ=
and QΩ=
- Let's substitute a by x and b by y
- PΩ=QΩ we substitute each distance by its expression
- After simplyfying the expressions we get finally : -12+8x-8y=0
- now we have -12x +8x-8y=0 and the line equation 3x+2y-16=0
- these are simultanious equations so after solving them we get x=3.8 wich is approximatively 4 and y=2
- we substitute a by 4 and y by 2 in PΩ to get the radius
- we get r =
= 4 - so r²= 16
- then the equation is : (x-4)²+(y-2)²=16
Answer:
-3
Step-by-step explanation:
4 (h+1.5)=-6
4h+6=-6
4h=-12
h=-3
Answer:
270 degrees counter-clockwise
Step-by-step explanation:
90 degree clockwise or 270 degree counter-clockwise
(x,y)----->'(y,-x)
Answer:
√34 or 5.83095189485
Step-by-step explanation:
√(3+2)^2 + (-1-2)^2
√(5^2 +-3^2)
√(25 +9)
√34
Answer:
The height of the lamp post is 15 feet ⇒ 1st answer
Step-by-step explanation:
The ladder , the lamp post and the ground formed a right triangle, the length of the ladder is its hypotenuse (l), the height of the lamp post (h) and the horizontal distance on the ground between the base of the ladder and the base of the lamp post (d) are the legs of the triangle
By using Pythagoras Theorem ⇒ <em>the square of the hypotenuse is equal to the sum of the squares of the other two legs</em>
∵ l² = h² + d²
∵ The length of the ladder is 25 feet
∴ l = 25
∵ The ladder is placed 20 feet from the lamp post
- That means the distance between the base of the ladder and
the base of the lamp post on the ground
∴ d = 20
- Substitute the values of l and d in the Pythagoras formula
∵ (25)² = h² + (20)²
∴ 625 = h² + 400
- Subtract 400 from both sides
∴ 225 = h²
- Take √ for both sides
∴ 15 = h
∴ The height of the lamp post is 15 feet
