Core Connections Algebra 2, 2013
CC
Core Connections Algebra 2, 2013 View details
3. Section 8.3
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Exercise 176 Page 429

Practice makes perfect
a We can write a quadratic function in factored form using the two given roots. Then we will change it to standard form by multiplying the factors.
Factored Form:& a(x-p)(x-q) Standard Form:& ax^2+bx+c In the factored form p and q are the roots of the function. Since we are told the roots are x = - i and x = i, we can partially write the factored form of our function. y = a( x-( - i ) ) ( x- i ) ⇕ y = a( x+ i ) ( x-i ) Since a does not have any effect on the roots, we can choose any value. For simplicity, we will let a=1. y = 1( x+ i ) ( x-i ) Finally, let's use the Distributive Property and Difference of Squares to obtain the standard form.
y = 1(x+i)(x-i)
â–Ľ
Simplify
y = (1x+1i)(x-i)
y = (x+i)(x-i)
y = x^2 - i^2
y = x^2 - (-1)
y = x^2+1
Please note that this is just one example of a quadratic function that satisfies the given requirements.
b We can write a quadratic function in factored form using the two given roots. Then we will change it to standard form by multiplying the factors.
Factored Form:& a(x-p)(x-q) Standard Form:& ax^2+bx+c In the factored form, p and q are the roots of the function. Since we are told the roots are x = 1+sqrt(2) and x = 1-sqrt(2), we can partially write the factored form of our function. y = a ( x - ( 1 + sqrt(2) ) ) ( x - ( 1 - sqrt(2)) ) ⇕ y = a( x-1-sqrt(2) ) ( x-1+sqrt(2) ) Since a does not have any effect on the roots, we can choose any value. For simplicity, we will let a=1. y = 1( x-1-sqrt(2) ) ( x-1+sqrt(2) ) Finally, let's use the Distributive Property to obtain the standard form.
y = 1( x-1-sqrt(2) ) ( x-1+sqrt(2) )
y = ( 1x-1(1)-1(sqrt(2)) ) ( x-1+sqrt(2) )
y = ( x-1-sqrt(2) ) ( x-1+sqrt(2) )
y = x( x-1+sqrt(2) )-1( x-1+sqrt(2) )-sqrt(2)( x-1+sqrt(2) )
â–Ľ
Distribute x & -1 & -sqrt(2)
y = x^2-x+sqrt(2)x-1( x-1+sqrt(2) )-sqrt(2)( x-1+sqrt(2) )
y = x^2-x+sqrt(2)x-x+1-sqrt(2)-sqrt(2)( x-1+sqrt(2) )
y = x^2-x+sqrt(2)x-x+1-sqrt(2)-sqrt(2)x+sqrt(2)-sqrt(2)(sqrt(2))
â–Ľ
Simplify
y = x^2-x+sqrt(2)x-x+1-sqrt(2)-sqrt(2)x+sqrt(2)-2
y = x^2-2x-1
Please note that this is just one example of a quadratic function that satisfies the given requirements.