I need to find slope of a curve

I have this graph plotted from FFT data (in excel). I need to find the slope of the curve seperately. so one value for line A (positive slope) and line B (negative slope). Idea is to get a ratio from that and compare the ratio with other samples. Usually i would go to my teacher but he is on holiday and i need this done well before he comes back.Also i am a complete novice when it comes to matlab, so a slightly detailed explanation would be very helpful. Thanks in advance.

Answer 1

[simone martinelli]

numA = xlsread(filename,sheet,xlRange) insert the range depending od quantity of data value A
numB = xlsread(filename,sheet,xlRange) insert the range depending od quantity of data value B

slopeA=diff(numA);% slope between different object of vector A

slopeB=diff(numB);% slope between different object of vector B