20. A line makes the same angle 0, with each of the x and z axis. If the angle B, which it makes with y- axis, is such that sin'B = 3sin'0, then cos 0 equals 1) 2/3 2) 1/5 3) 3/5 4) 2/5 (NUMERICAL VALUE TYPE) This section contains 5 questions. Each question is numerical value. For each question, enter the correct numerical value (in decimal notation, truncated/rounded-off to second decimal place. (e.g. 6.25, 7.00, -0.33, -.30, 30.27, -127.30). Marking scheme: +4 for correct answer, 0 if not attempted and 0 in all other cases. 21. If in a AABC the mid point of the sides AB,BC,CA are respectively (1,0,0), (0,m,0), AB? + BC? + CA and (0,0,n). Then P+m +n? 22. The angle between the lines joining the points (1,1,0). (-3, V3 + 1,3), and (0,-1,0), (-1, V3 -1,2) is cos If is an integer then 2is: 16 23. If e is the angle between two lines whose d.c's are (1,,m,,n) and (1,,m,,n,). Then the value +4)54 -4,) 4cos? 4 sin' 24. If origin is the orthocentre of a triangle formed by the points (cosa, sina,0).(cos ,sin B,0).(cosy,sin y,0) then Ecos(2a - - r)=_ 25. If A(3,4,5), B(4,6,3),C(3,-2,6) and D(1,0,5) are such that the acute angle n+ m between the lines DC and AB is 0,cos0= m:n then -