prove that 3 - 3 root under 2 is a rational number
Answers
Step-by-step explanation:
3+√2 = a/b ,where a and b are integers and b is not equal to zero .. therefore, √2 = (3b - a)/b is rational as a, b and 3 are integers.. But this contradicts the fact that √2 is irrational.. So, it concludes that 3+√2 is irrational..
Answer:
case 1
let us assume √2 is a rational number
√2=a\b where a and b are co- prime non negative integers
√2b = a. 1
squaring both the sides
(√2b)^2 = (a)^2
2b^2 = a^2
b^2 = a^2/2
therefore 2 is the common factor of a^2 and a a= 2c where c is some integer
equation 1 implies
√2b =a
squaring both the sides
2b^2 = 4c^2
b^2 = 2c^2
b^2/2 = c^2
therefore 2 is a common factor of b^2 and b
this controdict the fact that √2 is rational since 2 is a common factor of a and b
case 2
let us assume 3-3√2 is rational
3-3√2 = a/b where a and b are co- prime non negative integers
-3√2 = a/b -3
-3√2= a-3b/b
√2 = a-3b/b/-3
√2 = -3a+9b/b
√2 is irrational and -3a+9b/b is rational
so 3-3√2 is irrational