If sin theta = -(sqrt(3))/2 and pi < =theta <= (3pi)/2, determine the value of cos(20)

Sin theta = -1/2

Step-by-step explanation:

pi < =theta <= (3pi)/2.

The above expression shows we are dealing with angle on the 3rd quadrant.

I.e greater than 180 but less than 270.

So sin tita = (√3)/2

But sin and cos are all negative in the third quadrant.

So tita = sin^-1(√3)/2

tita = 60°

Cos tita = cos 60

Cos tita = cos 60

Cos60 = 0.5

Cos 60 = 1/2

If

sin theta = -(sqrt(3))/2

Sin theta = -1/2

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -

step-by-step explanation:

20-2= what