1/2+1/4+1/8+...+1/2^n=1-1/2^nUse math induction to prove that each statement is true for every positive integer n?
prove it is true for 1
(1/2)^1 = 1/2
1-(1/2)^1 = 1/2
now assume it is true for some integer k
1/2 + ... 1/2 ^ k = 1- 1/2^ k
now prove it is true for (k+1)
S( k+1) = 1-(1/2)^k + 1/2^(k+1)
S(k+1) = 1-(1/2)^k+1/2 (1/2^k)
S(k+1)=1- 1/2 (1/2)^k
S(k+1)= 1- (1/2)^ (k+1)
since it is also true for (k+1) this integer must be true for all positive integer n
hope this helps Use math induction to prove that each statement is true for every positive integer n?
n=1: 1/2^1 = 1 - 1/2^1. True for n = 1.
Now we must show that ';true for n = k'; implies ';true for n = k+1';. We do this by assuming the premise, and then we must use that to prove the conclusion. So assume:
1/2 + 1/4 + ... + 1/2^k = 1 - 1/2^k
Then we substitute the right hand side into the expression for k+1:
1/2 + 1/4 + ... + 1/2^(k+1) = 1 - 1/2^k + 1/2^(k+1)
But 2^(k+1) can also be written as 2 * 2^k, right hand side becomes:
1 - (2 - 1) / (2 * 2^k) = 1 - 1/2^(k+1)
Putting it together:
1/2 + 1/4 + ... + 1/2^(k+1) = 1 - 1/2^(k+1)
Completing the proof by induction.
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