Question

find the sum of first five term of the GP 1, 2, 4​

Answer 1

Answer:

31

Step-by-step explanation:

Given a=5,r=2,n=5

Sum=a(r^n-1)/r-1

S=1(2^5-1)/2-1

S=1(32-1)/1

S=1(31)

S=31

Answer 2

$Given \:G.P : 1, 2 ,4 ,$

$First \:term (a) = 1$

$Common \:ratio (r) = \frac{a_{2}}{a_{1}}\\= \frac{2}{1} = 1$

$\boxed { \pink {Sum \:of \: n \:terms S_{n} = \frac{a(r^{n} - 1 )}{r-1} }}$

$Sum \:of \: first \:5 \:terms \\= S_{5} = \frac{ 1( 2^{5} - 1)}{2-1} \\= 2^{5} - 1 \\= 32 - 1 \\= 31$

Therefore.,

$\red{Sum \:of \: first \:5 \:terms}\green { = 31 }$

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