EXERCISE 8.2

Q.2) Choose the correct option and justify your choice :

(ii)

Justification:

1

+

1

–

=

(1)²

(1)²

1

+

1

–

=

1

1

2

0

=

=

0

(A) tan 90º (B) 1 (C) sin 45º (D) 0

Hence, option (D) is correct.

∴

EXERCISE 8.2

Q.2) Choose the correct option and justify your choice :

Justification:

=

2

÷

1

+

1

²

=

2

÷

1

+

1

3

=

2

÷

1

3

3

+

=

2

÷

4

3

=

2

×

3

4

2

×

3

3

3

=

2

= sin 60º

∴

Hence, option (A) is correct.

(i)

=

(A) sin 60º (B) cos 60º (C) tan 60º (D) sin 30º

EXERCISE 8.2

Q.2) Choose the correct option and justify your choice :

(iv)

Justification:

=

2

×

÷

1

–

1

²

=

2

÷

1

–

1

3

=

2

3

÷

1

3

3

–

=

2

÷

2

3

=

2

3

×

3

2

=

=

tan 60°

∴

Hence, option (C) is correct.

(A) cos 60º (B) sin 60º (C) tan 60º (D) sin 30º

EXERCISE 8.2

Q.2) Choose the correct option and justify your choice :

(iii) sin 2A = 2 sin A is true when A =

Justification:

If A = 0º

sin 2 A

=

sin

(2

×

0º)

=

sin 0º

=

0

2 sin A

=

2 sin

0º

=

0

=

2 sin 0º

∴ sin 2A = 2 sin A, when A = 0º

Hence, option (A) is correct.

(A) 0º (B) 30º (C) 45º (D) 60º