So i just took my final exam and felt confident about it except for one question that sorta stumped me.

It is: find the first 6 a(sub)n numbers. Assume that the maclaurin series an*x^n is for (1+x+x^2)cosx.

I wasn't sure how you are suppose to get numbers with the X's in that summation.

I tried to write (1+x+x^2)cosx in the form of an*x^n and found that the numbers for a0 , a1, a2, a3 , a4 ,a5 = 1/2, 1/4!, 1/6!, 1/8!,1/10!