its using the Maclaurin series, i have already worked out the equations: cos x = 1 - (x^2)/2! + (x^4)/4! - (x^6)/6! + (x^8)/8! - (x^10)/10! + ... e^x = 1 + x + (x^2)/2! +(x^3)/3! + (x^4)/4! + (x^5)/5! + (x^6)/6! + ... how do i use these two results to obtain the first 6 terms on the maclaurin series for e^x.cos x? i've been working at this question for ages and cannot get it. thanks heaps if anyone can help me out.