if x= 1/3+2√2 , find the value of x-1/x
Answers
Answer: if x= 1/3+2√2 , find the value of x-1/x
Let √x - 1/√x = a
Squaring both the sides,
x + 1/x - 2 = a^2
Putting the value,
3–2√2 + 1/(3–2√2) - 2 = a^2
a^2 = 1 - 2√2 + 1/(3–2√2)
= [(3–2√2) (1–2√2) + 1] / 3–2√2
= {3 - 8√2 + 9} / 3–2√2
= [12 - 8√2] / 3–2√2
Rationalising both the sides
= {(12 - 8√2)(3+2√2)} ÷ (9–8)
= 36 + 24√2 - 24√2 + 16(2)
= 36 - 32
=> 4
a^2 = 4
[ OR]
((√x)-(1/√x))^2=x+(1/x)-2*x*(1/x).I.e
(a-b)^2=a*a+b*b-2*a*b.
((√x)-(1/√x))^2=(3–2√2)+(1/3–2√2)-2*(3–2√2)*(1/3–2√2).
Rationalising the above factor (3–2√2) I.e
Multiplying with (3+2√2) in numerator and denominator.so the result be (3+2√2).
((√x)-(1/√x))^2=(3–2√2)+(3+2√2)-2.
((√x)-(1/√x))^2=3+3–2=4.
Applying square root on both sides
(√x)-(1/√x)=2.
So the answer is 2.