The sum of the first \( n \) term of a series is given by \( S_{n}=2^{n+2}-4 \) Determine the sum of tle fiost 24 terms Determine the \( 24^{\text {th }} \) term. 3 Prove thiat the \( n^{\text {th }} \) term of the seres is \( 2^{n+1} \)
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To find the sum of the first 24 terms, we simply substitute \( n = 24 \) into the sum formula: \[ S_{24} = 2^{24+2} - 4 = 2^{26} - 4 = 67108864 - 4 = 67108860. \] So, the sum of the first 24 terms is \( 67108860 \). To find the \( 24^{\text{th}} \) term, denoted as \( T_{24} \), we can find it using the relationship \( T_n = S_n - S_{n-1} \): \[ S_{23} = 2^{23+2} - 4 = 2^{25} - 4 = 33554432 - 4 = 33554428, \] So, \[ T_{24} = S_{24} - S_{23} = 67108860 - 33554428 = 33554432. \] Now, to prove that the \( n^{\text{th }} \) term is \( 2^{n+1} \): Using the above relationship, we have \( T_n = S_n - S_{n-1} = (2^{n+2}-4) - (2^{(n-1)+2}-4) \). This simplifies to: \[ T_n = (2^{n+2} - 4) - (2^{n+1} - 4) = 2^{n+2} - 2^{n+1} = 2^{n+1} (2 - 1) = 2^{n+1}. \] Thus, it's proven that \( T_n = 2^{n+1} \).