Matlab R2014a version gives, -3.1175^0.5 = -1.7656 but (-3.1175)^0.5 = 0.0000 + 1.7656i Why?

Matlab R2014a version gives, -3.1175^0.5 = -1.7656 but (-3.1175)^0.5 = 0.0000 + 1.7656i

Why?

Answer 1

[Orion]

Because of the parenthesis.

The power operation is executed before the minus operation, so

-3.1175^0.5

is strictly equivalent to :

-(3.1175^0.5)

which is not the same as

(-3.1175)^0.5

Answer 2

[Steven Lord]

The power operator ^ has higher precedence than the unary minus operator - but parentheses () have higher precedence than either ^ or -.