Write a polynomial equation of degree 4 in standard form that has the solutions i, −i, 1, −1.

x⁴ + 2 x² + 1

Step-by-step explanation:

given solution of the polynomial

i, −i, 1, −1.                        

equation of the polynomial will be equal to

 =(x - i)(x + i)(x - 1)(x + 1)                      

 = (x² + i x - i x - i²)(x² + x - x + 1)            

 =(x² - (-1))(x² + 1 )                        

 = (x² + 1)(x² + 1)                        

= x⁴ + x² + x² + 1                          

= x⁴ + 2 x² + 1                                    

hence, the required polynomial equation is x⁴ + 2 x² + 1          

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!