Indeterminate means uncertain as to the extent, amount is not established, undefined, not fixed. Indeterminate is an adjective, derived words are indeterminacy, indeterminately, indeterminateness.
Indeterminable means unable to ascertain the extent, unable to establish an amount, unable to define. Indeterminable is an adjective, indeterminably is the related adverb. Both indeterminate and indeterminable are derived from the Late Latin word indeterminabilis which means cannot be defined, and from the prefix in- which means not.
The difference between indeterminate and indeterminable: indeterminate indicates something that is not defined or established, indeterminable indicates something that it is not possible to define or establish.
The idea of an early production soybean system using indeterminate varieties has been around for decades, but it wasn’t a particularly economic way to grow soybeans in the Southeast. (The Southeast Farm Press)
“City of Thorns” winds down to an indeterminate end, as shifting as its people. (The Seattle Times)
Like a paint box where all the lively reds and yellows and blues have been mixed in together, blending into a sad, dirty, indeterminate kind of colour. (The Independent)
But the rest of those who wisely invested in a Windows Phone and can’t wait to upgrade for a chance to run Universal Applications and Project Continuum are being forced to wait in a queue of indeterminate length. (The Register)
Investigators found the “details are indeterminable and must remain largely conjectural. (The New Zealand Press)
“Orders” boasts the drama of real life: its unpredictability, indeterminable motives, outcomes that are never final. (The Chicago Tribune)
“I believed it was part of a greater design,” Stanley says in hindsight, “and surely, supernatural reasoning aside, it was of indeterminable practical value to the economy of the South.” (The New York Times)
Whether he has had a change of heart on the subject or whether his assertion is merely theatrical is indeterminable. (The Indian Express)