2 - Area bounded region, volume, surface area and arc length Questions Answers

length for one turn = 3

Draw diagonal of a rectangle then turn it as a cylinder, you will get the construction given in the question.

$$\begin{gathered} In triangle l = \sqrt{3^2+n^2} \\ So total length of wire having n turn = n\sqrt{3^2+n^2} \\ Compare with 20 and solve \end{gathered}$$

[sinx + cosx] = [√2 sin{x+(π/4)}]    here [ ] is greatest integer function

its value in different interval are

1       for 0 to π/2

0       for π/2 to 3π/4

-1        for 3π/4 to π

-2     for π to 3π/2

-1     for 3π/2 to 7π/4

0      for 7π/4 to 2π

now solve