Marking Scheme

SRE-231
Proved.
1
19
( ) ) ( )
or
1
1
1
1
correct figure with of information
=elevation from A to C
A
C
E
20
1
( )
B
D
1
( )
or, √
1
or, m √
Height of tower ( )
21
√
( √ )
√
Let BAC is angle on the Circumference of a semi -circle with centre O
and the diameter BC.
A
1. A
1
1
B
O
C
⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗
⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ 1
⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ) ( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ )
= ( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ) ( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ )
b
1
( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ )= (OC 2 b
OA 2 b
)
⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ ( ⃗⃗⃗⃗⃗ ⃗⃗⃗⃗⃗ )
BAC= 90 o 1
6