Prove that (√2 + √3) is an irrational number, it is given that √2 is an irrational number. About the author Emma
Answer: Let √3 – √2 be a rational number , say r Then √3 – √2 = r On squaring both sides we have (√3 – √2)2 = r2 3 – 2 √6 + 2 = r2 5 – 2 √6 = r2 -2 √6 = r2 – 5 √6 = – (r2 – 5) / 2 Now – (r2 – 5) / 2 is a rational number and √6 is an irrational number . Since a rational number cannot be equal to an irrational number . Our assumption that √3 – √2 is rational is wrong Reply
Answer:
Let √3 – √2 be a rational number , say r
Then √3 – √2 = r
On squaring both sides we have
(√3 – √2)2 = r2
3 – 2 √6 + 2 = r2
5 – 2 √6 = r2
-2 √6 = r2 – 5
√6 = – (r2 – 5) / 2
Now – (r2 – 5) / 2 is a rational number and √6 is an irrational number .
Since a rational number cannot be equal to an irrational number . Our assumption that
√3 – √2 is rational is wrong