Please help!! posting pic below!!
@Luigi0210
@Nnesha
@Michele_Laino can you help me???
please ive been stuck on this :/
hint: as we can see, from the graph, the center of the circle, is: \[\Large C = \left( { - 1.5,1.5} \right)\] so if we consider any generic point \(P=(x,y)\) of the circle, the distance \(PC\), is: \[\Large d\left( {C,P} \right) = \sqrt {{{\left( {x - \left( { - 1.5} \right)} \right)}^2} + {{\left( {y - 1.5} \right)}^2}} \]
So C?
hint: of course, such distance, has to be equal to the radius of the circle, and the radius of the circle is \(r=3/2=...\)
that's right!
Choose the correct standard form of the equation of a circle given the following radius and coordinates. r = 11, (0, 0) Select one: a. x^2 + y^2 = 121 b. (x – 0)^2 + (y – 11)^2 = 0 c. Either A or B d. None of the above
I confirm option C
can you help me with the question i posted above ?
since the center is \(C=(0,0)\), and the radius is \(r=11\), then the distance \(d\) of a generic point of the circle from the center, is: \[d\left( {C,P} \right) = \sqrt {{{\left( {x - 0} \right)}^2} + {{\left( {y - 0} \right)}^2}} \] again such distance has to be equal to the radius of the circle
So theres more than one option? so C?
I think that there is only one correct option
I think B
hint: from my replies above, we can write this: \[\sqrt {{{\left( {x - 0} \right)}^2} + {{\left( {y - 0} \right)}^2}} = 11\]
yeah B
hint: if I take the square of both sides of last equation, I get: \[{\left( {x - 0} \right)^2} + {\left( {y - 0} \right)^2} = {\left( {11} \right)^2}\]
D?
I think it is option A, since we can write this: \[\begin{gathered} {\left( {x - 0} \right)^2} + {\left( {y - 0} \right)^2} = {x^2} + {y^2} \hfill \\ {\left( {11} \right)^2} = 121 \hfill \\ \end{gathered} \]
oh okay
Choose the correct standard form of the equation of a circle given the following radius and coordinates. r = 4, (–2, 8) Select one: a. x2 + y2 = 4 b. (x – 2)^2 + (y – 8)^2 = 16 c. (x + 2)^2 + (y + 8)^2 = 4 d. (x + 2)^2 + (y – 8)^2 = 16
again, we can write this equation for the distance between a generic point \(P=(x,y)\) and the center of the circle \(C=(-2,8)\): \[d\left( {C,P} \right) = \sqrt {{{\left( {x - \left( { - 2} \right)} \right)}^2} + {{\left( {y - 8} \right)}^2}} = 4\]
now, please take the square of such equation, namely: \[{\left( {\sqrt {{{\left( {x - \left( { - 2} \right)} \right)}^2} + {{\left( {y - 8} \right)}^2}} } \right)^2} = {4^2}\]
C?
no, I'm sorry, since \(4^2=16\)
hint: after a simplification, we get: \[{\left( {x - \left( { - 2} \right)} \right)^2} + {\left( {y - 8} \right)^2} = 16\]
D or B
B
yes! So, option D or option B?
B right??
no, I'm sorry, option B is wrong, since in my equation we have: \[x - \left( { - 2} \right) = x + 2\]
oh okay i got my signs messed up
would you mind?
if not its ok
I think that the point \((1,0)\) is the center, right?
i believe so
so, we can write this equation for the distance between a generic point \(P=(x,y)\) from the center: \[\sqrt {{{\left( {x - 1} \right)}^2} + {{\left( {y - 0} \right)}^2}} = {\left( {\frac{1}{4}} \right)^2}\]
and that leaves us with either A or C i believe
oops.. I have made a typo: \[\sqrt {{{\left( {x - 1} \right)}^2} + {{\left( {y - 0} \right)}^2}} = \frac{1}{4}\]
hint: again, if I take the square of both sides of such equation, I can write: \[{\left( {x - 1} \right)^2} + {\left( {y - 0} \right)^2} = {\left( {\frac{1}{4}} \right)^2}\]
oh no B then
yes! that's right!
thanks so much (:
:)
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