Quadratic Equation Is Probable?
I
f
m
ϵ
N
s
u
c
h
t
h
a
t
m
≤
5
t
h
e
n
p
r
o
b
a
b
i
l
i
t
y
t
h
a
t
q
u
a
d
r
a
t
i
c
e
q
u
a
t
i
o
n
x
2
+
m
x
+
1
/
2
+
m
/
2
=
0
h
a
s
r
e
a
l
r
o
o
t
s
i
s
?
The answer is 0.6.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
Nice solution.
Log in to reply
same way too btw whats your score in jstse mock test.reply fast
Log in to reply
Who Are You? And what is JSTSE Mock Test?
Log in to reply
@Hrisheek Yadav – dont u know?its me kaustubh miglani of fiitjee dwarka and i was asking for ur marks in the test u gave on monday since result of it wasnt out by then
Log in to reply
@Kaustubh Miglani – You must be a friend of my bro...
Log in to reply
@Hrisheek Yadav – idk.i am a friend of hrisheek yadav and u may be his brother using his account.
Log in to reply
@Kaustubh Miglani – He is studying in England by the way..
Log in to reply
@Hrisheek Yadav – is he???? hahaha no jokes buddy.i met him or should i say u yesterday only.
Log in to reply
@Kaustubh Miglani – There ain't only one of this name man
Log in to reply
@Hrisheek Yadav – i am sure its u and u may try to fool me but sorry i wont be a victim of it
Log in to reply
@Kaustubh Miglani – What r u talking about?????? I aint no goofing Around
The equation a x 2 + b x + c has real roots if the discriminant D = b 2 − 4 a c > 0 .
For x 2 + m x + 2 1 + 2 m this means D = m 2 − 4 ( 2 1 + 2 m ) = m 2 − 2 m − 2 > 0 . We find the zeroes of this expression: m 2 − 2 m − 2 = 0 ⟹ ( m − 1 ) 2 = 3 ⟹ m = 1 ± 3 . From m ≥ 1 + 3 we find that m ∈ { 3 , 4 , 5 } , so that the probability is P = # { 1 , 2 , 3 , 4 , 5 } # { 3 , 4 , 5 } = 5 3 = 0 . 6 .