Show that if a and b are real, the principal value of arg a is 0 or ti according as a is positive or negative and that of bi is `pi/2 or -pi/2` according as b is positive or negative.

Show that if a and b are real,the principal value of arg a is 0or ti according as a is positive or negative and that of bi is (pi)/(2) or -(pi)/(2) according as b is positive or negative.

-(2pi)/(5) is the principal value of

The function f(x) = sin x-x cos x is: (A).maximum or minimum for all integral multiple of pi (B) maximum if x is an odd positive or even negative integral multiple of pi (C) minimum if x is an even positive or odd negative integral multiple of pi (D) None of these

Tell if - 2 (1)/(5) - (-2 (3)/(16) ) is positive or negative. Explain.

Which type of lens has a) a positive power, and b) a negative power?

If a,b,c are sides of a scalene triangle,then value of |abcbcacab| is (a)positive (b) negative (c)non-positive (d) non-negative

The least numerical value, either positive or negative of angle theta is called principal value of the inverse trigonometric function.

(a) The linear magnification of a concave lens is always positive. Why? (b) The linear magnification of a convex lens may be positive or negative. Why ?

Show that arg. overline(z)=2pi-arg.z.