Question:১১.`x = (4ab)/(a + b)` হলে, দেখাও যে,
`(x + 2a)/(x - 2a) + (x + 2b)/(x + 2b) = 2, a != b`
Answer ১০. সমাধান:
দেওয়া আছে,
`x = (4ab)/(a + b)`
বা, `x = (2a xx 2b)/(a + b)`
`:. x/(2a) = (2b)/(a + b)`
এবং `x/( 2b) = (2a)/(a + b)`
যখন, `x/(2a) = (2b)/(a + b)`
তখন, `(x + 2a)/(x - 2a) = (2b + a + b)/(2b - a - b)` [ যোজন-বিয়োজন করে ]
`:. (x + 2a)/(x - 2a) = (a + 3b)/(b - a)` .........(i)
আবার, যখন `x/( 2b) = (2a)/(a + b)`
তখন, `(x + 2b)/(x - 2b) = (2a + a + b)/(2a - a - b)` [ যোজন-বিয়োজন করে ]
`:. (x + 2b)/(x - 2b) = (3a + b)/(a - b)`..........(ii)
(i) নং এবং (ii) নং সমীকরণ যোগ করে পাই,
`(x + 2a)/(x - 2a) + (x + 2b)/(x - 2b) = (a + 3b)/(b - a) + (3a + b)/(a - b)`
`= (a + 3b)/(b - a) + (3a + b)/( - (b - a))`
`= (a + 3b)/(b - a) - (3a + b)/(b - a)`
`= (a + 3b - (3a + b))/(b - a)`
`= (2b - 2a)/(b - a)`
`= (2(b - a))/((b - a))`
`= 2`
`:. (x + 2a)/(x - 2a) + (x + 2b)/(x + 2b) = 2` ( দেখানো হলো )