Is that all the question says? If not, please say what else it says.
Answer is 9
Step by step explanation
As CB is radius CB=3, CA=3+7=10
X^2=(7+3)^2-3^2=100-9=81
X=9
(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
B. Between 20 and 25 minuets
Brooke's speed is decreasing between 20 and 25 minutes. According to the graph Brooke's speed is decreasing during that time period.