Well,
arctan is a bijection from R into (-pi/2 , pi/2)*and
pi is a period of tangent function:
so
as we have : tan(7pi/4) = tan(pi - pi/4) = - tan(pi/4)
we finally get :
<span>arctan(tan(7pi/4)) = artan(tan(- pi/4)) = - pi/4
</span>
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1) % = (Wo /Wi) * 100
Solve for Wo => Wo = (% / 100) * Wi
For example, % =30% and Wi = 250 => Wo = (30 /100) * 250 = 0.30 * 250 = 75
Wo = 75
2) % = (Wo / Wi) * 100
Solve for Wi
=> Wi = Wo * (%/100)
For example, Wo = 125 and % = 40%
=> Wi = 125 * (40 / 100) = 125 * 0.40 = 50
Wi = 50
Use of fossil fuels has not lead to increased use of wood as heat source.
Answer: Option D
<u>Explanation:</u>
Fossil fuels are materials required to generate heat or thermal energy and they are obtained by the decomposed remains of plants, animals and human beings. But the fossil fuels generally present in the bottom layer of earth crust or sometimes mixed with stones or rock minerals. So we need to highly energetic drilling devices to extract the fossil fuels.
Thus, before the introduction of fossil fuels, wood is used as the igniting source for heat energy. But the entry of fossil fuels have reduced the use of wood as igniting source in cooking, burning etc.
Thus, the use of fossil fuels have increased exchange of culture and ideas as fuels are mostly imported from other nations, it lead to development of faster transportation methods and increased the availability of products including heat, plastics and medicine. But similarly, the use of fossil fuels have not increased the use of wood as heat source, instead it decreased the use of wood as heat source.
Answer:
1. 23°
2. 65°
Explanation:
1.
The law of reflection provides that for the same medium, the angle of reflection equals the angle of incidence.
Similarly, here, angle of incidence and reflection will be 46°÷2=23°
2. Since the normal, angles of reflection and incidence lie on the same plane and also the angles of reflection and incidence are equal then the angle between the plane of the mirror and the reflected beam will be given by 90-25=65°
