Conic Sections Question 489

Question: If the chord y=mx+1 of the circle $ x^{2}+y^{2}=1 $ subtends an angle of measure $ 45{}^\circ $ at the major segment of the circle, then the value of m is

Options:

A) $ 2\pm \sqrt{2} $

B) $ -2\pm \sqrt{2} $

C) $ -1\pm \sqrt{2} $

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

[c] From the figure, $ OB=1,OD=\frac{1}{\sqrt{2}} $ Also, $ OD=\frac{| m(0)-0+1 |}{\sqrt{m^{2}+1}} $ So, we have $ \frac{| m(0)-0+1 |}{\sqrt{m^{2}+1}}=\frac{1}{\sqrt{2}} $
$ \therefore m=\pm 1 $