3
6. The
are
vertices of a triangle
A(2,3,5)}(-1,3,2), (3,5,-2), then the angles
are
1) 30°, 30°, 120°
2) Cos-1
1
15
,90º, Cos-1
5
13
3) 30°, 60°, 90°
1
4) Cost
900, Cos
√3
2
13
Answers
Answer:
see below
Step-by-step explanation:
11th
Maths
Introduction to Three Dimensional Geometry
Distance between Two Points
The vertices of a triangle ...
MATHS
The vertices of a triangle are )2,3,5),(−1,3,2),(3,5,−2), then the angles are
EASY
Study later
ANSWER
AB
=−3
i
^
−3
k
^
BC
=4
i
^
+2
j
^
−4
k
^
CA
=−
i
^
−2
j
^
+7
k
^
cosA=
∣
∣
∣
∣
AB
∣
∣
∣
∣
.
∣
∣
∣
∣
CA
∣
∣
∣
∣
∣
∣
∣
∣
AB
.
CA
∣
∣
∣
∣
=
3
1
⇒A=cos
−1
(
3
1
)
cosB=
∣
∣
∣
∣
AB
∣
∣
∣
∣
.
∣
∣
∣
∣
BC
∣
∣
∣
∣
∣
∣
∣
∣
AB
.
BC
∣
∣
∣
∣
=0
⇒B=90
∘
cosC=
∣
∣
∣
∣
CA
∣
∣
∣
∣
.
∣
∣
∣
∣
BC
∣
∣
∣
∣
∣
∣
∣
∣
CA
.
BC
∣
∣
∣
∣
=
3
2
⇒C=cos
−1
(
3
2
)