The number of point F (x) =(x , if x is a rational )
( 0 , if x is irrational) is continuous at? a) -1 b) infinity c ) 2 d) 3
Answers
Answer:
At x=0
x→0
+
lim
f(x)=0
(Same for rational and irrational)
Also
x→0 −lim
f(x)=0
So it is continuous at x=0
At other number it's limit is not defined in it's neighbourhood as it can be x or 0 when x
=0 it is not continuous.
So f(x) is continuous only at 0
Answer:
A man is four times as old as his Son.
After four years the man will be thrice as old as his son.
-------------------------------
♠ To Find :-
The Present Ages of Both.
-------------------------------
♠ Solution :-
Let Present age of Son be = x years
So, Present age of Man will be = 4x years
《After4 Years》
《After4 Years》
Age of Man = (4x + 4) years
Age of Son = (x + 4) years
}
(4x+4)=3(x+4)
4x+4=3x+12
4x−3x=12−4
:⟼
x=8years
,
4x=4×8
:⟼
4x=32years
Present age of Man = 32 years
Present age of Son = 8 years.
-----------------------