Question

Which set of ordered pairs goes with y = 2cos x ?

Answer 1

Set of ordered pairs = { ( 0 , 2 ), ( π / 2 , 0) , ( π , -2) , ( 2 π , 2)}

Explanation:

Given y = 2 cos x

i) Let x =0 ⇒ y = 2 cos (0) = 2

The ordered pair ( 0 , 2 )

ii) Let x = π / 2 ⇒ y = 2 cos (π/2) = 2(0) =0

The ordered pair ( π / 2 , 0)

iii) let x = π ⇒ y = 2 cos(π) = 2 (-1) = -2

The ordered pair ( π , -2)

iv)

let x = 2π ⇒ y = 2 cos(2π) = 2 (1) = 2

The ordered pair ( 2 π , 2)

Set of ordered pairs = { ( 0 , 2 ), ( π / 2 , 0) , ( π , -2) , ( 2 π , 2)}