Sagot :
Answer:
Well, we have to see for three cases- i. x<1 , ii. 1<x<2 and iii. x>2 .
We need not consider 1 and 2 since we can see that the equation is not satisfied for x=1 or x=2 .
Case i.
x<1ā¹xā1<0ā¹|xā1|=ā(xā1)=1āx and |xā2|=ā(xā2)=2āx ( āµx<1,ā“x<2 and xā2<0 )
So here we get the equation as 1āx+2āx=4 , which gives 2x=ā1.
ā“x=ā12=ā0.5 .
What is the solution of |x-1|+|x-2|ā„4?
Well, we have to see for three cases- i. x<1 , ii. 1<x<2 and iii. x>2 .
We need not consider 1 and 2 since we can see that the equation is not satisfied for x=1 or x=2 .
Case i.
x<1ā¹xā1<0ā¹|xā1|=ā(xā1)=1āx and |xā2|=ā(xā2)=2āx ( āµx<1,ā“x<2 and xā2<0 )
So here we get the equation as 1āx+2āx=4 , which gives 2x=ā1.
ā“x=ā12=ā0.5 .
Case ii.
1<x<2ā¹xā1>0 but xā2<0 . ā“|xā1|=xā1 and |xā2|=2āx
So here we get the equation as xā1+2āx=4ā¹1=4 which is not possible.
Hence we do not have any solution for the equation in the interval (1,2) .
Case iii.
x>2ā¹x>1 . Hence xā1>0 and xā2>0 .
ā“|xā1|=xā1 and |xā2|=xā2
So the equation becomes xā1+xā2=4 , which gives 2x=7 .
ā“x=72=3.5 .
Hence we get two solutions for the given equation:
x=ā12 and x=72
Why did we divide the domain (i.e. the set of real numbers) into three such parts?
If we want to define f(x)=|xā1|+|xā2| without using modulus symbols we would have to do it in the following way.
In other words, f(x) is not differentiable at x=1 and x=2 .
Step-by-step explanation: