Define f(x) = , Then :
f is increasing only in the interval
f is decreasing in the interval
f attains maximum at x =
f attains minimum at x =
The interior angles of a polygon are AP. The smallest angle is 120° and the common difference is 5°. The number of sides of the polygon is :
9
10
16
5
A.
9
Let there be n sides of the polygon. Then, the sum of all interior angles is (2n - 4) right angles.
But for n = 16, the largest angle 1i 120 + (16 - 1) 5 = 195, which is impossible
Hence, n = 9.