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samnatha
Group Title
help me please
Find the equation of the tangents to the circle x^2 + y^2  6x  2y  15 = 0 which are parallel to the line 3x + 4y + 10 = 0
 one year ago
 one year ago
samnatha Group Title
help me please Find the equation of the tangents to the circle x^2 + y^2  6x  2y  15 = 0 which are parallel to the line 3x + 4y + 10 = 0
 one year ago
 one year ago

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shubhamsrg Group TitleBest ResponseYou've already chosen the best response.0
find dy/dx of the circle and the line.. equate both since both are parallel and thus find out the eqn..
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
whats the dy/dx ?
 one year ago

shubhamsrg Group TitleBest ResponseYou've already chosen the best response.0
i see..why are you studying tangents then ? you need to clear up the basics first..
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
am well my teacher probably does it a different way than you do...
 one year ago

shubhamsrg Group TitleBest ResponseYou've already chosen the best response.0
hmm..what does he do? differentiate instead of finding dy/dx? o.O
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
no we have never done differentiate yet just what does dy/ dx stand for ?
 one year ago

shubhamsrg Group TitleBest ResponseYou've already chosen the best response.0
it'll come after you differentiate,,nevermind,,must be some alternative way then..
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
like usually we would just sub one of the equations in but i tried doin it like that and it just looks complicated
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
hmmm.. i think he not yet learned about differentiate so, for basic u can use the formula : y  b = m(xa) +  r*sqrt(m^2+1) with a,b is the center of circle, m slope and r radius therefore, first u have to determines all components above
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
ok that seems more familiar we use the formula y  y1 = m(xx1)
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
that is the equation of the tangents to the circle sign + means there are 2 equations there so, if given equation of circle : x^2 + y^2  6x  2y  15 = 0 what;s the center of circle and it radius ?
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
(3,1) is the center and the radius is 5
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
yes.. correct next can u determine the slope of line which parallel with line 3x + 4y + 10 = 0 ?
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
is it 3 ?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
use the property : m1 = m2 (because the lines are parallel) hint : if given a straight line ax+by+c=0, to find slope u can use the formula m=a/b
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
so the slope would be 3/4 ?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
looks too many formula above, hahaha...
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
haha is it right ?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
yes, of couse
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
oh thank god haha
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
u just plug of them, write out ur equation welcome...
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
the answer in the back of the book id diff from the answer i got
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
what's the book answer ?
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
3x + 4y + 12 =0 or 3x + 4y  38 = 0
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
wait, i will check it...
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
ok thanks :)
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
the formula above have worked... i got like ur book answer
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
i have no idea where i went wrong ?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
ok, let's check it steps by steps...
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
first, we have the center of circle (3,1) and its radius = 5 right ?
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
oh wait i know what i did i didn't use the whole formula only the first part
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
then the sope of line 3x+4y+10=0 is m1=3/4 so, m2 = 3/4 also (because parallel)
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
i got so far 3x+4y  13 = + 25(25/16) ?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
now, aplly of them to the formula : y  b = m(xa) +  r*sqrt(m^2+1) y1 = 3/4(x3) +  5 * sqrt((3/4)^2 + 1) y1 = 3/4(x3) +  5 * sqrt(25/16) y1 = 3/4(x3) +  5 * 5/4 y1 = 3/4(x3) +  25/4 multiply by 4 to both sides, gives 4(y1) = 3(x3) + 25 4y  4 = 3x + 9 + 25 3x + 4y  4 9 + 25 = 0 3x + 4y  13 +  25 = 0 the first equation : 3x + 4y  13 + 25 = 0 3x + 4y + 12 = 0 2nd equation : 3x + 4y  13  25 = 0 3x + 4y  38 = 0
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
whats *sqrt ? is it square root?
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
* the symbol of multiplication sqrt = square root
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
oooh thats what i was doing rong i didn't know what that was :P
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
hahahaha... u must KNOW it
 one year ago

samnatha Group TitleBest ResponseYou've already chosen the best response.0
haha sorry yeah i got it now i was squaring 5 :P whoops thanks for your help
 one year ago

RadEn Group TitleBest ResponseYou've already chosen the best response.1
you're welcome :)
 one year ago
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