Question

If tane = root2-1, then the value of sine cose is
3.
(1)
1
12
1
(2)
2
2
(3)
4
4 43
(4)

Answer 1

Answer:

tanA=

2

−1

we know tanA=

B

P

=

1

2

−1

∴H=

(

2

−1)

2

+1

2

=

4−2

2

∴sinA=

4−2

2

2

−1

cosA=

4−2

2

1

∴sinAcosA=

4

−2

2

2

−1

×

4−2

2

1

=

4−2

2

2

−1

=

4−2

2

2

−1

×

4+2

2

4+2

2

=

16−8

4

2

+4−4−2

2

=

8

2

2

=

4

2