Answer: Option d.
Step-by-step explanation:
The trigonometric identity needed is:

Knowing that
:
Substitute it into
:

Simplify the expression:

Solve for
. Apply square root at both sides of the expression:


Answer:
21.68 minutes ≈ 21.7 minutes
Step-by-step explanation:
Given:

Initial temperature
T = 100°C
Final temperature = 60°C
Temperature after (t = 3 minutes) = 90°C
Now,
using the given equation

at T = 90°C and t = 3 minutes


or

taking the natural log both sides, we get
3k = 
or
3k = -0.2876
or
k = -0.09589
Therefore,
substituting k in 1 for time at temperature, T = 65°C

or

or

or

taking the natural log both the sides, we get
( -0.09589)t = ln(0.125)
or
( -0.09589)t = -2.0794
or
t = 21.68 minutes ≈ 21.7 minutes
The x-intercept is where the graph crosses the x-axis. that happens when y=0.
x + 2(0) = 5
x = 5
x-intercept is 5
The heat of the sun penetrates the atmosphere and warms the Earth's surface. The warmed rEarth Radiates and this heat back into the atmosphere.The gases the surround the atmosphere such as carbon dioxide , methane , nitrous oxide and water vapour absorb some of the radiated heat and send it back to the Earth . This<em> trapping of heat from the Sun by excess carbon dioxide and other gases present in the atmosphere</em> is known as the <u>greenhouse effect</u>. The gases involved in the phenomenon are called <u>greenhouse gases.</u>
<h3>Hope it helps ~(•‿•)</h3>