Re: Complex solve a equation
Amer said:
how to solve this equation in complex
\sqrt{x+8} + 2 = \sqrt{x}
Thanks
Hi Amer, :)
Suppose that a complex solution exists for this equation. Let,
\[\sqrt{x+8}=r_1 e^{i\theta_1}\mbox{ and }\sqrt{x}=r_2 e^{i\theta_2}\]
Then by \(\sqrt{x+8} + 2 = \sqrt{x}\) we get,
\[r_1\cos\theta_1+2=r_2\cos\theta_2~~~~~~~~~~~(1)\]
and,
\[r_1\sin\theta_1=r_2\sin\theta_2~~~~~~~~~~~(2)\]
Also,
\[\sqrt{x+8}=r_1 e^{i\theta_1}\mbox{ and }\sqrt{x}=r_2 e^{i\theta_2}\]
\[\Rightarrow r^{2}_2 e^{2i\theta_2}+8=r^{2}_1 e^{2i\theta_1}\]
\[\Rightarrow r^{2}_1\sin2\theta_1=r^{2}_2\sin2\theta_2\]
\[\Rightarrow r^{2}_1\sin\theta_1\cos\theta_1=r^{2}_2\sin\theta_2\cos\theta_2~~~~~~~~~~~(3)\]
By (2) and (3),
\[r_1\cos\theta_1=r_2\cos\theta_2~~~~~~~~~~~(4)\]
Therefore by (1) and (4),
\[2=0\]
which is a contradiction. Hence there exist no solutions for the equation,
\[\sqrt{x+8} + 2 = \sqrt{x}\]
Wolfram verifies this. :)
Kind Regards,
Sudharaka.