Question

Which of the following is not true?
a) sin⁡θ=-3/4 b) cos⁡θ=-1 c) tan⁡θ=25 d) sec⁡θ=1/4

Answer 1

Answer:

b) cosA = -1

Step-by-step explanation:

A angle can never be negative

Answer 2

Concept:

We will recall the definition of trigonometry to answer this question.

Trigonometry is the branch of mathematics which deals with the study of angles, sides of figures using functions like sine, cosine, tangent, cot etc

Given:

We are given the following:

• sin $\Theta$=-3/4
• cos $\Theta$=-1
• tan $\Theta$=25
• sec $\Theta$=1/4

To find:

We are asked to find which one of the following is false

Solution:

From the following given, the fourth option given seems wrong.

Let's justify our claim

We are given: sec $\Theta$=1/4

And we know from formulas of trigonometry that:

cos $\Theta$= 1/ sec $\Theta$

cos $\Theta$=1/(1/4)

cos $\Theta$=4

But the domain of cosine is maximum up to 1.

Thus, option d) sec $\Theta$=1/4 is not true