Letx=√6+√6+√6+√6+...∞
On squaring both sides,
x2=6+√6+√6+√6+√6+...∞
x2=6+x
x2−x−6=0
x=1±√12−4×1×(−6)2(1)
x=1±√252=1±52
∴x=3 or x=−2
Since a negative number cannot be under root, hence x=3
Question 4(d) :
Look at the figures and write ‘<’ or ‘>’ between the given pairs of fractions:
66□33
Given a = 6 + √3 ⇒ (1/a) = 1 / (6 + √3) Multiply and divide by (6 − √3) ⇒ (1/a) = (6− √3) / [(6 + √3)(6 − √3)] ⇒ (1/a) = (6 − √3) / [36 − 3] ⇒ (1/a) = (6− √3)/33 ∴ a - (1/a) = (6 + √3) -(6 − √3)/33 = [33(6 + √3) - (6 - √3)]/33 = [32*6 + 34*√3]/33 = [192 + 34√3]/33 Answer : [192 + 34√3]/33
Why does 1/a come above