I'm helping my 7th grader and reviewing his math homework, and I still can't quite figure out one problem. I know I'm overthinking this.








 
 
 

Operator precedence of exponentiation?

Squaring a number is higher priority than the minus sign.

That is, you aren't squaring -6, you are squaring 6 then negating the result.


It is the same as times and divide come before plus and minus, doing roots and exponents (in this case squaring) comes before times, divide, plus and minus.


See http://en.wikipedia.org/wiki/Order_of_operations

-6^2 = 36.

-(6^2)= -36

Yeah, I figured out that was the case. But it's, at best, poorly written. Putting it in parentheses makes it crystal clear.

 


 

In a written out polynomial -5x^2-6x-7 = 0 it is interpreted as -(5(x^2)) - (6x) -7 = 0 since multiplication (and exponentiation is multiplication) takes precedence over subtraction (or addition) in each term.

Trig and other functions can make a real mess out of a polynomial so just put in the extra parenthesis.

You also need to now if a -1 power directly on a trgi function is also takes as the inverse function (arcsin) and not 1/sin x.  (sin x)^-1 would be 1/sin x.