You're given that φ is an angle that terminates in the third quadrant (III). This means that both cos(φ) and sin(φ), and thus sec(φ) and csc(φ), are negative.
Recall the Pythagorean identity,
cos²(φ) + sin²(φ) = 1
Multiply the equation uniformly by 1/cos²(φ),
cos²(φ)/cos²(φ) + sin²(φ)/cos²(φ) = 1/cos²(φ)
1 + tan²(φ) = sec²(φ)
Solve for sec(φ) :
sec(φ) = - √(1 + tan²(φ))
Given that cot(φ) = 1/4, we have tan(φ) = 1/cot(φ) = 1/(1/4) = 4. Then
sec(φ) = - √(1 + 4²) = -√17
Answer:
This proof can be done by contradiction.
Let us assume that 2 - √2 is rational number.
So, by the definition of rational number, we can write it as
where a & b are any integer.
⇒ 
Since, a and b are integers 
is also rational.
and therefore √2 is rational number.
This contradicts the fact that √2 is irrational number.
Hence our assumption that 2 - √2 is rational number is false.
Therefore, 2 - √2 is irrational number.
Do u have a pic of the problem?
Answer:
For the sum of the digits of Michelle’s father to drop to 1/3 of its’ former value, the second digit must go from 9 to 0, in one year.
Thus, if he is 39 this year, the sum of the digits of his age will be 12. Next year, when the sum of the digits would be 4+0, or 4, then the digits of his age would be 1/3rd of their former value.
Therefore, he is 39, and will be 40 next year
Step-by-step explanation:
I believe it'd be the one with the smiley emoji
