+0

# Trig question help. Please explain. I think the answer is supposed to be -1 but how do you know that it cannot be the other choices?

0
65
2

Trig question help. Please explain. I think the answer is supposed to be -1 but how do you know that it cannot be the other choices?

Guest Feb 14, 2018
edited by Guest  Feb 14, 2018
Sort:

### 2+0 Answers

#1
+85668
+1

Look at the secant graph here :

https://www.desmos.com/calculator/g2ulbffk6j

Note  that  the range  is   ( - inf, -1 ] U [ 1, inf )

So.....the secant's  range  always has an absolute value   ≥  1

Only the first answer  meets that criteria....so....you are correct  !!

CPhill  Feb 15, 2018
#2
+1773
+1

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

Mellie  Feb 15, 2018

### 8 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details