ton A = 1/2and tan B = 1/3 l then fin the
Value of
(A + B)
-22/7/4
Answers
Answered by
1
Step-by-step explanation:
cosA+cosB=1
⇒2cos(
2
A+B
)cos(
2
A−B
)=1
Since A+B=
3
π
⇒
2
A+B
=
6
π
Hence cos(
3
A+B
)=cos(
6
π
)=
2
3
⇒2cos(
2
A−B
)=
2
3
1
⇒cos(
2
A−B
)=
3
1
Squaring both sides, we get
cos
2
(
2
A−B
)=
3
1
⇒2cos
2
(
2
A−B
)=
3
2
⇒2cos
2
(
2
A−B
)−1=
3
2
−1=cos(A−B)=
3
−1
∣cosA−cosB∣=2sin(
2
A+B
)sin(
2
B−A
)
=2×
2
1
1−
3
1
=
3
2
(on simplification)
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