Question

8.
In a right angle triangle ABC, right angle is at B, if tan A= 13 then find the value of
(i) sin A cos C + cos A sin C
(ii) cos A cos C-sin A sin C​

Answer 1

Answer:

In △ABC,

∠B=90

o

, tanA=

3

1

=

AB

BC

Let BC =1x,AB=

3

x

AC

2

=AB

2

+BC

2

AC

2

=(

3

x)

2

+(x)

2

=4x

2

AC=2x

(i) sinAcosC+cosAsinC=

2

1

×

2

1

+

2

3

×

2

3

=

4

1

+

4

3

=1

(ii) cosAcosC−sinAsinC=

2

3

×

2

1

−

2

1

×

2

3

=

4

3

−

4

3

=0