1.

For what value of n, are the nth terms of two A. Ps 63, 65, 67,.... and 3, 10, 17,.... equal?

Answer» First APs63, 65, 67, ......Here, a = 63d = 65 - 63 = 2{tex}\\therefore {/tex}\xa0nth term = 63 + (n - 1)2\xa0{tex}\\because {/tex}\xa0an = a + (n - 1)dSecond APs3, 10, 17, .....Here, a = 3d = 10 - 3 = 7{tex}\\therefore {/tex}\xa0nth term = 3 + (n - 1)7\xa0{tex}\\because {/tex}\xa0an = a+(n - 1)dIf the n th terms of two APs are equal then63 + (n - 1)2 = 3 + (n - 1)7{tex} \\Rightarrow {/tex}\xa0(n - 1)2 - (n - 1)7 = 3 - 63{tex} \\Rightarrow {/tex}\xa0(n - 1) (2 - 7) = -60{tex} \\Rightarrow {/tex}\xa0(n - 1) (-5) = -60{tex} \\Rightarrow n - 1 = \\frac{{ - 60}}{{ - 5}}{/tex}{tex} \\Rightarrow {/tex}\xa0n - 1 = 12{tex} \\Rightarrow {/tex}\xa0n = 12 + 1{tex} \\Rightarrow {/tex}\xa0n = 13Hence, for n = 13th terms of the two APs are equal


Discussion

No Comment Found