Jambmaths question:
A binary operation on the set of real numbers excluding –1 is such that, for all m, n $\varepsilon $ R, $m\Delta n=m+n+mn$. Find the identity element of the operation
Option A:
1
Option B:
0
Option C:
$-\frac{1){2}$
Option D:
-1
Jamb Maths Solution:
$\begin{align} & m\Delta n=m+n+mn \\ & m\Delta e=m+e+me=m\text{ (}e\text{ is the identity element)} \\ & e+me=0 \\ & e(1+m)=0 \\ & e=\frac{0}{1+m} \\ & e=0 \\\end{align}$
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