SOLUTION: Determine the equation of the inverse for the quadratic equation f(x)=6x^2+11 I don’t know how to do this one since my teacher didn’t explain this one

Algebra ->  College  -> Linear Algebra -> SOLUTION: Determine the equation of the inverse for the quadratic equation f(x)=6x^2+11 I don’t know how to do this one since my teacher didn’t explain this one      Log On


   



Question 1197339: Determine the equation of the inverse for the quadratic equation
f(x)=6x^2+11

I don’t know how to do this one since my teacher didn’t explain this one

Found 2 solutions by math_tutor2020, MathLover1:
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

Graph out y = 6x^2+11 to find that it fails the horizontal line test.

It is possible to draw a single horizontal line through more than one point on the parabola.
This function is not one-to-one, i.e. the function is not injective.

As such, no inverse exists if we account for the entire domain of f(x) = 6x^2+11

But if we restrict the domain to x+%3E=+0, then the graph passes the horizontal line test. This is the right hand side of the parabola.

The outline to finding the inverse follows these steps
1) Replace f(x) with y
2) Swap x and y
3) Solve for y

Let's follow that process
f(x) = 6x^2+11
y = 6x^2+11
x = 6y^2+11
x-11 = 6y^2
6y^2 = x-11
y^2 = (x-11)/6
y = sqrt( (x-11)/6 )


The inverse is

The green graph represents the original function f(x) = 6x^2+11 but only when x+%3E=+0
The inverse is the blue curve, which is a reflection of the green curve over the dashed purple line y = x

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=6x%5E2%2B11
to determine the equation of the inverse for the quadratic equation, recall that +f%28x%29=y
y=6x%5E2%2B11...... swap variables
x=6y%5E2%2B11..........solve for y
x-11=6y%5E2
%28x-11%29%2F6=y%5E2
y=sqrt%28%28x-11%29%2F6%29

ysqrt%28x+-+11%29%2Fsqrt%286%29

so, inverse is
f'%28x%29= ± sqrt%28x+-+11%29%2Fsqrt%286%29