if the 21st term of an a.p. 25 find the sum of its first 41 term
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Hi Mate!!!
21ist term = a + 20d = 25
Multiple both sides by 2
2a + 40d = 50.... equation 1
Sum of ist 41 terms of an ap is
S41th = 41 / 2 { 2a + ( 40 ) d }
S41th = 41 / 2 { 50 }
S41th = 1025
Have a nice day
21ist term = a + 20d = 25
Multiple both sides by 2
2a + 40d = 50.... equation 1
Sum of ist 41 terms of an ap is
S41th = 41 / 2 { 2a + ( 40 ) d }
S41th = 41 / 2 { 50 }
S41th = 1025
Have a nice day
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