1.

If x=√3+√2 then find the value of x^3 + 1/x^3 ?A) 6√3 B)12√3 C)18√3 D)24√3

Answer» (a+b) ^3 = a^3 + b^3 + 3ab(a+b)------->a^3 + b^3 = (a+b)^3 -- 3ab(a+b)similary:- if, a = x and b = 1/x then x^3 + 1/x^3 = (x + 1/x)^3 -- 3x*1/x(x + 1/x) =(x + 1/x)^3 -- 3(x + 1/x) 1/x = 1/√3 + √2 =1*√3 -- √2/√3 + √2*√3 -- √2 =√3 -- √2/(√3) ^2 -- (√2) ^2 =√3 -- √2/3 -- 2 =√3 -- √2x + 1/x = √3 + √2 + √3 -- √2 =2√3 Putting in equation in 5th line = (2√3) ^3 -- 3(2√3) =24√3 -- 6√3 =18√3 ANSWER = 18√3
C)
The correct answer is (A).


Discussion

No Comment Found