Prove that the following is irrational 7 root3 - 3
Answers
Answer:
for √3:
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.
√3 = p/q { where p and q are co- prime}
√3q = p
Now, by squaring both the side gives:
(√3q)² = p²
3q² = p² ........ ( i )
if 3 is the factor of p² , then, 3 is also a factor of p
Let p = 3m { where m is any integer }
squaring both sides gives:
p² = (3m)²
p² = 9m²
putting the value of p² in equation ( i )
3q² = p²
3q² = 9m²
q² = 3m²
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:
let us suppose that 7√3 - 3 is rational.
then there exists two positive integers a and b which are co primes such that:
7√3 - 3 = a/b
7√3 = a/b - 3
7√3 = a-3b/b
√3 = a-3b/7b
a-3b/7b = rational number but we know that √3 is irrational( proved above)
rational number ≠ irrational number
hence our supposition is wrong
therefore, 7√3 - 3 is irrational
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Answer:
Step-by-step explanation:
Let assume that 7√3-3 as a rational number if possible ....
Let 7√3-3 =a/b
7√3=a-3b/b
√3=a-3b/7b
Integer-integer/integer
= A rational number ...
Here,√3 is a rational no.but we contradicts that √3 is an irrational no.
So, 7√3-3 is an. Irrational number.......
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