x + x- 1 = 2 হলে x201 + x309 মান নিচের কোনটি?
সমাধান
সঠিক উত্তর: Option C
x + x- 1 = 2
⇒ x + 1/x = 2
⇒ (x2 + 1)/x = 2
⇒ x2 + 1 = 2x
⇒ x2 - 2x + 1 = 0
⇒ (x - 1)2 = 0
⇒ x - 1 = 0
∴ x = 1
এখন
x201 + x309 = 1201 + 1309
= 1 + 1 = 2
⇒ x + 1/x = 2
⇒ (x2 + 1)/x = 2
⇒ x2 + 1 = 2x
⇒ x2 - 2x + 1 = 0
⇒ (x - 1)2 = 0
⇒ x - 1 = 0
∴ x = 1
এখন
x201 + x309 = 1201 + 1309
= 1 + 1 = 2
