Hello;

1) I need to calculate M43:: sum[m=1 to m=9] G(m)*sin(m*x) for a value of
"x" tabulated in column L.
The 9 values of "m" are tabulated in $D$21:$D$29
The 9 values of G(m) are tabulated in $C$21:$C$29
The first x value is in cell L43

Can someone please help in deriving the array formula to be entered in M43 ??
For other values of x in L44, L45, ... one would simply copy M43 and paste
in M44, M45, ...

2) The following formula "obviously" doesn't work:
M43::{=SUMPRODUCT($C$21:$C$29,SIN(PRODUCT($D$21:$D $29,L43)))}

3) If it's not too much trouble, how about:
N43:: -sum[m=1 to m=9] G(m)*cos(m*x)/m for each value of tabulated x

Your help would be greatly appreciated.

Regards