Question

Suppose theta is an angle in standard position with cos theta > 0. In which quadrants could the terminal side of theta lie? Select two answers.

I
II
III
IV

Answer 1

the correct answers are -

I and IV

Answer 2

Here given cos Θ >0. That means cos Θ is positive.

We know that, cos Θ = (adjacent)/(hypotenuse) = $\frac{x}{r}$

We also know that, hypotenuse can not be negative. So we will get cos positive where x co-ordinate is positive.

In first quadrant we will get positive x axis, in second quadrant there is negative x axis and same for third quadrant. In fourth quadrant we will get again positive x axis.

So cos is positive in first and fourth quadrant. Therefore, terminal side of theta lies in first and fourth quadrant.

We have got the required answer.

Option 1 and 4 is correct.