(tanθ + cotθ)² = sec²θ + csc²θ
<u>Expand left side</u>: tan²θ + 2tanθcotθ + cot²θ
<u>Evaluate middle term</u>: 2tanθcotθ = 
= 2
⇒ tan²θ + 2+ cot²θ
= tan²θ + 1 + 1 + cot²θ
<u>Apply trig identity:</u> tan²θ + 1 = sec²θ
⇒ sec²θ + 1 + cot²θ
<u>Apply trig identity:</u> 1 + cot²θ = csc²θ
⇒ sec²θ + csc²θ
Left side equals Right side so equation is verified
<span>3 + (-1/4)² ÷ 1/2
= </span><span>3 + 1/16 * 2
= 3 + 1/8
= 3 1/8
answer
</span><span>D. 3 1/8</span>
Answer:
?
Step-by-step explanation:
Answer: cos(Θ) = (√15) / 4
Explanation:
The question states:
1) sin(Θ) = 1/4
2) 0 < Θ < π / 2
3) find cos(Θ)
This is how you solve it.
1) Use the fundamental identity (in this part I use α instead of Θ, just for facility of wirting the symbols, but they mean the same for the case).
2) From which you can find:
3) Replace sin(α) with 1/4
=>
=>
4) Given that the angle is in the first quadrant, you know that cosine is positive and the final answer is:
cos(Θ) =
.
And that is the answer.
