Question

a central angle T, of a unit circle has the terminal side in the fourth quadrant and has a cosine of X. what is the cosine of T+(pi/2)?A) 2XB) -XC) (X/2)D) X

Answer 1

The terminal side is in the fourth quadrant,

In fourth quadrant the cosine value are greater than or equal to zero,

When we rotate the angle by pi/2, the terminal side will be in first quadrant,

where in first quadrant all the values are positive,

so the value of cosine cannot be negative

Option B. -X is not possible,

Thus, 2X, X/2, X can be possible

the value of Cosine is X

and the value of Cos(T+90)=CosTCos90-SinTSin90

Cos(T+90)=X(0)-cos(90-T)1

Cos(T+90)=0-(-X)1

Cos(T+90)=X

ANSWER :

D. X