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Find the 8^th term of the geometric sequence 
4,-12,36,dots
Answer:

Find the 8th 8^{\text {th }} term of the geometric sequence 4,12,36, 4,-12,36, \ldots \newlineAnswer:

Full solution

Q. Find the 8th 8^{\text {th }} term of the geometric sequence 4,12,36, 4,-12,36, \ldots \newlineAnswer:
  1. Find Common Ratio: To find the 8th8^{\text{th}} term of a geometric sequence, we need to know the common ratio. The common ratio (rr) is the factor by which we multiply one term to get the next term.\newlineWe can find the common ratio by dividing the second term by the first term.\newliner=124r = \frac{-12}{4}
  2. Calculate Common Ratio: Now, let's calculate the common ratio using the values from the sequence. r=(12)/4=3r = (-12) / 4 = -3
  3. Use Geometric Sequence Formula: With the common ratio found, we can use the formula for the nth term of a geometric sequence, which is an=a1×r(n1)a_n = a_1 \times r^{(n-1)}, where a1a_1 is the first term and nn is the term number.\newlineFor the 88th term (a8a_8), we have:\newlinea8=4×(3)(81)a_8 = 4 \times (-3)^{(8-1)}
  4. Calculate Exponent: Now we calculate the exponent part of the formula.(3)81=(3)7(-3)^{8-1} = (-3)^7
  5. Calculate (3)7(-3)^7: Calculating (3)7(-3)^7 gives us:\newline(3)7=3×3×3×3×3×3×3=2187(-3)^7 = -3 \times -3 \times -3 \times -3 \times -3 \times -3 \times -3 = -2187
  6. Multiply First Term: Now we multiply the first term of the sequence by the result of the exponent calculation to find the 8th8^{\text{th}} term.a8=4×(2187)a_8 = 4 \times (-2187)
  7. Find 88th Term: Multiplying 44 by 2187-2187 gives us the 88th term of the sequence.\newlinea8=4×(2187)=8748a_8 = 4 \times (-2187) = -8748

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