Delta symbol( upside down triangle?

Question

Delta symbol( upside down triangle?

Answer 1

upper case delta is Δ

lower case delta is δ

both are letters in the Greek alphabet.

If you really want an upside down triangle, try ▽

.

Answer 2

DELTA, the upright triangle with the apex pointing upward, is used in engineering normally to indicate a change. Example;

DELTA T means change in temperature.

In Naval Architecture, DELTA is used to denote displacement. The reverse of DELTA, which is the upside down triangle is used to denote volume of displacement.

Answer 3

Pronounced "del", the upside down triangle is a symbol indicating the gradient of a function.

See

http://mathworld.wolfram.com/Del.html