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If second term of AP is 4 and sixth term is 12 then find tenth term |
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Answer» 20 is correct Answer.. {tex}\\eqalign{ & {t_2} = 4 \\cr & {t_6} = 12 \\cr & {t_n} = a + (n - 1)d \\cr & a + d = 4 \\cr & a + 5d = 12 \\cr & d = 2 \\cr & a = 2 \\cr & so\\,{t_{10}} = a + 9d \\cr & = 20 \\cr } {/tex} tn=a+(n-1)d -------1Subs n=2 in 1t2=a+(1)d=4Subs n=6 in 1t6= a+(5)d=12 a+5d=12 a+1d= 4 ___________(-) 4d= 8 d=2a+d=4a+2=4 a=2Subs n=10 in 1t10=a+9d =2+9(2) t10=20 therefore the 10th term is 20 |
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