If a quadratic equation has multiple roots, then it's discriminant cannot be zero.
[MATH](4\cos(\theta))^2-4(1)(\cot(\theta))\ne0[/MATH]
Given the restriction on θ, we hay divide through by 4cos(θ) to obtain:
[MATH]4\cos(\theta)-\csc(\theta)\ne0[/MATH]
[MATH]4\sin(\theta)\cos(\theta)-1\ne0[/MATH]
[MATH]2\sin(2\theta)-1\ne0[/MATH]
I think the problem should have stated the quadratic has a single root of multiplicity 2 (repeated root), so that we equate the discriminant to zero.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.