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| 1. |
Which term of AP . 121, 117 ,113, ....... is its first negative term? |
| Answer» Given: 121, 117, 113, .......Here a = 121, d = 117 - 121 = 4Now, an = a + (n - 1)d= 121 + (n - 1) (-4) = 121 - 4n + 4 = 125 - 4nFor the first negative term, an < 0{tex} \\Rightarrow 125 - 4n < 0 \\Rightarrow 125 < 4n \\Rightarrow \\frac{{125}}{4} < n{/tex}{tex} \\Rightarrow 31\\frac{1}{4} < n{/tex}n is an integer and {tex}n > 31\\frac{1}{4}{/tex}.Hence, the first negative term is 32nd term | |