Question

if sin(θ-30°)=1/2,then cos θ=?​

Answer 1

Step-by-step explanation:

Explanation:

(

sin

t

−

cos

t

)

2

=

1

−

2

sin

t

.

cos

t

(

sin

t

+

cos

t

)

2

=

1

+

2

sin

t

.

cos

t

Add up the 2 equations:

(

sin

t

−

cos

t

)

2

+

(

sin

t

+

cos

t

)

2

=

2

From given data -->

(

sin

t

−

cos

t

)

2

=

(

1

2

)

2

=

1

4

Therefore:

(

sin

t

+

cos

t

)

2

=

2

−

1

4

=

7

4

(

sin

t

+

cos

t

)

=

±

√

7

2

hope it helps

Answer 2

Answer:

1/2

Step-by-step explanation:

$sin(\theta-30) = \frac{1}{2}$

$=> sin(\theta-30) = sin(30)\\=> \theta - 30 = 30\\=> \theta = 60$

therefore, $cos(\theta) = cos(60) = 1/2$