Question

If 1, a and P are in A. P. and 1, g and P are in G. P., then

• A. $1+2a+g^2=0$
• B. $1+2a-g^2=0$
• C. $1-2a-g^2=0$
• D. $1-2a+g^2=0$

Answer 1

Answer: (D)

$2a=1+p$ and $g^2=P$
$\Rightarrow g^2=2a-1\Rightarrow 1-2a+g^2=0$