clearmountain wrote:

Hi.

i had an inscribed angle problem asking for the lenght of one of the sides.

the answer was 4 +2rad2.

the answer key says I am supposed to get this by factoring this quadratic y^2 + 8Y + 8 = 0.

how do i do that?

thanks,

Clearmountain

If the answer is \(4+2\sqrt{2}\) then the equation must be \(y^2-8y+8=0\).

You can use the formula which gives the roots of a quadratic equation in terms of its coefficient.

Another way is as follows:

\(y^2-8y+8=y^2-8y+16-8=(y-4)^2-8=0\) from which \((y-4)^2=8\) and either \(y-4=2\sqrt{2}\), so \(y=4+2\sqrt{2}\),

or \(y-4=-2\sqrt{2}\), which gives \(y = 4-2\sqrt{2}\).

_________________

PhD in Applied Mathematics

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