Question

find value of tan-1(1/11)+cot-1(6/5)
​

Answer 1

Answer:

Correct option is C)

tan

−1

6

5

+

2

1

tan

−1

60

11

2

1

tan

−1

(

1−(

6

5

)

2

6

5

×2

)+

2

1

tan

−1

(

60

11

)[∵2tan

−1

x=tan

−1

1−x

2

2x

]

=

2

1

tan

−1

(

11

60

)+

2

1

tan

−1

(

60

11

)

=

2

1

[cot

−1

(

60

11

)+tan

−1

(

60

11

)][tan

−1

x=cot

−1

x

1

]

=

2

1

×

2

π

=

4

π

Because[cot

−1

x+tan

−1

x=

2

π

]