How to Use Negative Exponents on a Scientific Calculator

[krimsondane]

Homework Statement

PV = PMT *1-(1+i)^-n / i
PV = 225 * 1- (1+.0055)^-42 / .005
PV = 8417.37

How did they get this. how do you use a negative exponent on a scientific calculator.

Homework Equations

The Attempt at a Solution

 

[krimsondane]

sorry for not using ? How did they get this? How do you use a negative exponent on a scientific calculator?

 

[Mark44]

Does your calculator have a Change Sign button? They are sometimes marked +/-.

 

[krimsondane]

Does your calculator have a Change Sign button? They are sometimes marked +/-.

No it does not I have a texas instruments TI-30x IIS model scientific calculator with 2 lines

 

[Mark44]

What does the button labelled (-) do? Looks like to me it would change the sign. If that's not it, take a look at the manual - http://education.ti.com/educationportal/sites/US/productDetail/us_ti30x_iis.html?bid=6

 

[krimsondane]

Homework Statement

PV = PMT *1-(1+i)^-n / i
PV = 225 * 1- (1+.0055)^-42 / .005
PV = 8417.37

How did they get this. how do you use a negative exponent on a scientific calculator. I have a calculator, just don't know how to use it correctly.

Homework Equations

The Attempt at a Solution

thx a lot