An even function can be reflected about the y axis and map onto itself
example: y=x^2
an odd function can be reflected about the origin and map onto itself
example: y=x^3
a simple test is the following
if f(x) is even then f(-x)=f(x)
if f(x) is odd then f(-x)=-f(x)
so
even function
subsitute -x for each and see if we get the same function
remember to fully expand these
g(x)=(x-1)^2+1=x^2-2x+1+1=x^2-2x+2 is the original one
g(x)=(x-1)^2+1
g(-x)=(-x-1)^2+1
g(-x)=(1)(x+1)^2+1
g(-x)=x^2+2x+1+1
g(-x)=x^2+2x+2
not same because the original has -2x
not even
g(x)=2x^2+1
g(-x)=2(-x)^2+1
g(-x)=2x^2+1
same, it's even
g(x)=4x+2
g(-x)=4(-x)+2
g(-x)=-4x+2
not the same, not even
g(x)=2x
g(-x)=2(-x)
g(-x)=-2x
not same, not even
g(x)=2x²+1 is the even function
A two-digit number is twice the sum of its digit. If the tens digit is 7 less than the unit digit, find the number.
Let x= the unit digit
Then y= the tens digit
<span>And 10y+x= the number
</span>x+y= the sum of the digits
<span>Now we are told that 10y+x=2(x+y) ------1st equation </span>
<span>We are also told that y=x-7 ----------- 2nd Equation </span>
<span>So our equations to solve are: </span>
(1) 10y+x=2(x+y)
<span>(2) y=x-7
</span>
Hope it helps
Would it be 5 ? i’m sorry i’m not very sure.
The complete question in the attached figure
we know that
[Area of her bedroom]=[11*10]+[12*8/2]+[10*6]------> 218 ft²
the answer Part A) is
Are needed 218 ft² of carpeting for the room
[perimeter of her bedroom]=[11+10+11]+[12]+[6+10+6]+[8]-------> 74 ft
the answer Part B) is
Are needed 74 ft <span>
of baseboards</span>
for the room
1+3+5+7+...+999 =
= 1+2+3+4+...+500
+1+2+3+...+499
= 2·(1+2+3+...+499) + 500
= 2·(499·500)/2 + 500
= 499·500 + 500
= 500·(499 + 1)
= 500·500
= 250.000
