A very good question

A variable st. line cuts off from the given st. lines concurrent at origin,intercepts ,the sum of reciprocals of which is a non zero constant K.Show that varibale line passes through a fixed pt. whose coordinates are (i=1)Σ(n) cos@i/K , (i=1)Σ(n) sin@i/K where @i is the given n values

2 Answers

1
skygirl ·

cudn get a hint of the question..
plz clarify.. someone..

62
Lokesh Verma ·

let the lines be

y=x tan(@i)

let the variable line be y=mx+c

This line cuts y=x tan(@i) at x(tan(@i)-m)=c

x=c/(tan(@i)-m)
y=c.tan(@i)/(tan(@i)-m)

Length fo the inercept is c sec(@i)/(tan(@i)-m)

=c / {(sin(@i) - m cos(@i) }

reciprocal of lenthg of the intercept is {(sin(@i) - m cos(@i) }/c

Sum of the length is constant!!!!

{Σ(sin(@i) - mΣ cos(@i) }/c =K

Does this give the hint???????/

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