How can I use symsum to write a sum of functions?

I want to set x = .1*sin(2*pi*.1*t) + .2*sin(2*pi*.2*t) + ... + .9*sin(2*pi*.9*t) using summation notation (for example if I want increments of .01 instead of .1 this would be helpful). I've tried:

y = symsum((k/10)*sin(2*pi*(.2 + (k/100))*t), k, 1, 9);

where t is a time vector. Then I try an FFT this data but I get:

Undefined function 'fft' for input arguments of type 'sym'.

Error in SampleFFT (line 16) Y = fft(y,NFFT)/L;

But the y should not be symbolic input, because t varies for all values in the vector and k varies from 1 to 9, so why doesn't it come out to numeric values? Please help me figure out how to get a sum of a series of functions.