Linear space: which subset of V is lin. dependent?

[karan]

Let V be the linear space of all real-valued funtions defined on the real line.Which of the following subsets of V is linearly dependent

(a) {e^ax, x*e^ax, x^2*e^ax}
(b) {cos^2 x, sin^2 x}
(c) {1,cos 2x, sin^2 x}
(d) {sinx,cosx}

 

[royhaas]

Re: Linear space

Hint: use trig identities.