We know that sec(x) is equal to cos(x) because it is the reciprocal of cosine.
So, choice d cannot be correct because cos(x) cannot be 0, because it would result in an undefined answer.
We we know that cosine is adjacent/ hypotenuse. Of course, the reciprocal would be hypotenuse/adjacent.
If if you look at choice b, c, and e, the numerators (hypotenuse) are all smaller than the denominator (adjacent side). This is not possible because the hypotenuse in a triangle cannot be less than one side.
this is why choice A must be correct
We know that 23pi/2 is in between 270°(3pi/2) and 360°(2pi).
So, it's reference angle is 24pi/12 - 23pi/2 (because 2pi/1 is equal to 24pi/12).
The reference angle will be pi/12.
We know that sin+cos is equal to 90. and 90° in radians is pi/2. So, (pi/2) - (pi/12) will give you the value of theta, which is 5pi/12
Ok. So, you want to find n. To do that, we can first combine like terms. 6n+2n. Just like regular addition, 8n. The outcome would be 8n=72. So, if we want to find n, we need to somehow eliminate the 8. Since 8 multiplied by n would give us 72, we need to divide eight from both sides to get our final answer. So 72/8=9. n=9