Syntax :

=LOGEST(known_y’s, [known_x’s], [const], [stats])

Parameters :

• The primary statistical information supplied is an array of constants for the exponential curve equation, mn, mn-1,…, b (or the constants m and b if there is just one range of x-values). You can, however, request that extra regression statistics be supplied.

known y’s – 

• A collection of known y-values.

[known x’s] –

• An optional parameter that returns an array containing one or more sets of known x-values.
  If supplied, the [known x’s] array should have the same length as the known y’s array; if not provided, the [known x’s] array assumes the default value of 1, 2, 3.

[const] –

• A logical argument that specifies how the constant ‘b’ is handled in the exponential curve equation y = b*mx. This parameter might be TRUE or FALSE, which means that
• TRUE (or omitted) – the constant b is processed normally.
• FALSE – in the equation y = b*mx, the variable b is set to 1.

[stats] –

• An optional logical parameter that determines whether the function should return extra regression statistics on the generated curve. This parameter can be TRUE or FALSE, which means: FALSE (or omitted) if more regression statistics are not returned. That is, just return the array of values mn, mn-1,…, b.
• TRUE – Additional regression statistics ARE RETURNED.