Prove that √3 is an irrational number
Answers
Answer:
If possible , let
3
be a rational number and its simplest form be
b
a
then, a and b are integers having no common factor
other than 1 and b
=0.
Now,
3
=
b
a
⟹3=
b
2
a
2
(On squaring both sides )
or, 3b
2
=a
2
.......(i)
⟹3 divides a
2
(∵3 divides 3b
2
)
⟹3 divides a
Let a=3c for some integer c
Putting a=3c in (i), we get
or, 3b
2
=9c
2
⟹b
2
=3c
2
⟹3 divides b
2
(∵3 divides 3c
2
)
⟹3 divides a
Thus 3 is a common factor of a and b
This contradicts the fact that a and b have no common factor other than 1.
The contradiction arises by assuming
3
is a rational.
Hence,
3
is irrational.
2
nd
part
If possible, Let (7+2
3
) be a rational number.
⟹7−(7+2
3
) is a rational
∴ −2
3
is a rational.
This contradicts the fact that −2
3
is an irrational number.
Since, the contradiction arises by assuming 7+2
3
is a rational.
Hence, 7+2
3
is irrational.
Proved.
Answer:
Prove that ✓3 is irrational numbers
Let us assume that √3 is a rational number.
then, as we know a rational number should be in the form of p/q
where p and q are co- prime number.
So,
√3 = p/q { where p and q are co- prime}
√3q = p
Now, by squaring both the side
we get,
(√3q)² = p²
3q² = p² ........ ( i )
So,
if 3 is the factor of p²
then, 3 is also a factor of p ..... ( ii )
=> Let p = 3m { where m is any integer }
squaring both sides
p² = (3m)²
p² = 9m²
putting the value of p² in equation ( i )
3q² = p²
3q² = 9m²
q² = 3m²
So,
if 3 is factor of q²
then, 3 is also factor of q
Since
3 is factor of p & q both
So, our assumption that p & q are co- prime is wrong
hence,. √3 is an irrational number
Step-by-step explanation:
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