1.

Consider three points `P = (-sin (beta-alpha), -cos beta)`, `Q = (cos(beta-alpha), sin beta)`, and `R = ((cos (beta - alpha + theta), sin (beta - theta))`, where `0< alpha, beta, theta < pi/4` ThenA. P lies on the line segmennt RQB. Q lies on the line segmet PRC. R lies on the line segment QPD. P,Q,R are non-colinear

Answer» Correct Answer - D
Let the coordinates of P and Q be `(x_(1),y_(1)) and (x_(2),y_(2))` respectively. Then `x_(1)=sin (beta-alpha), y_(1)=- cos beta, x_(2)= cos (beta-alpha),y_(2)= sin beta`. The coordinates of R are `(cos (beta-alpha+theta), sin (beta-theta))` ,
`or , (cos(beta-alpha)cos theta-sin theta(beta-alpha)sin theta, sin beta cos theta-cos beta sin theta)`
`or (x_(1) sin theta+x_(2)cos, theta, y_(1)sin theta+y_(2) theta)`
We observe that the poins having coordinates
`((x_(1) sin theta+x_(2)cos theta)/(sin theta+ cos theta),(y_(1)sin theta+y_(2) cos theta)/(sin theta+cos theta))`
divides PQ internally in the ratio `cos theta: sin theta` .
So, P,Q S are coolinerr points. But P,Q R are non-Collinear.


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