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If the 2nd term of an A.P is 8 and the 5th term is 17 find its 19th term? |
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Answer» 59. If 2nd term is 8 So..a,a+d,a+2d....a+d=8................ Equation no.1Then...The 5th term is 17...Again same ...But now it\'s 5th term so ....a+4d=a5 I.e. a+4d=17................... Equation no.2Therefore....From 1 and 2a+d=8a+4d=17Now by elimination method....And subtracting Equation.no.1 from 2 ....We get ......Now a will be cancelled out ....So ...Remaining is...-3d=-9Therefore... d=3....... Equation.no.3.Now putting the value of d in 1 equation ...We get...a+d=8,a+3=8a=8-3Therefore...a=5...Now at the last ....U got a and d so form the AP and get the answer....No no don\'t form AP ...Then we will ...Put all the values in the formula An=a+(n-1)dA19=5+(19-1)×3A19=5+18×3A19=5+54A19=59Therefore....19th term of an AP is 59..., 59 Sorry 59 is correct. Its 59 54. |
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