#Mark the correct alternative in each of the following
The sum of two non-zero numbers is 8, the minimum value of the sum of their reciprocals is
Let the two non zero numbers be x and y.
so,x+y=8
y=8-x
and,
put y=8-x in f(x,y)
therefore it will become a function in
f’(x)=0
⇒ x=8-x
x=4
Hence by second derivative test
f’’(x)>0 so it’s a point of minimum.
Hence at x=4 minimum value
Option(B)