Dear fellow Excel users out there,

does anyone know if there is a function in Excel similar to TREND that
interpolates linearly between data points instead of returning a linear trend
for the hole array.

Example:

Known x's Known y's
1 2
2 5
3 6
4 8

=TREND(known_y's;known_x's;1.5) delivers 3.35 but I need a function that
delivers 3.5 (because 1.5 is in the middle between 1 and 2, and 3.5 is in the
middle between 2 and 5, i.e. the linear interpolation between the two data
points).