 ## Even-Odd Properties?

Use the even-odd properties to find the exact value of each trig expression below. DO NOT USE a calculator.

(1) cos(-30 degrees)

(2) sin(-135 degrees)

(3) csc(-pi/4)

(1) cos(-30 degrees) = cos(30) = (√3)/2

(2) sin(-135 degrees) = -sin(135) = -sin(45) = -(√2)/2

(3) csc(-pi/4) = 1/sin(-pi/4) = -1/sin(pi/4) = -1/(1/√2) = -√2 ## Common TI-89 calculator problem or no?

My TI-89 graphing calculator started acting strange about two days ago. the screen is vertically split into two where the left looks normal and then the right side is MUCH darker. Adjusting the contrast to see the darkened side results in the left side being completely invisible. I replaced the batteries and that obviously wasn’t the problem. I can’t download games or anything for that matter on to this type of calculator so there isn’t a game that’s messing up the memory. It hasn’t touched (or been near) water and it hasn’t been dropped. It’s only a few years old. So what may be the cause of this odd phenomena? Is there a safe (yet effective) way to reverse the problem?

That has never happened to me. Something might have just happened inside the calculator with the screen causing it to look like that. You should try out their website or something. (if they have one.) ## need help with my scientific calculator please?

hi guys just a quick question. i know how to use the calculator to calculate the pH but i can’t remember how to punch in times by odd number exa..(^-7)

pH = –log [H3O+]
= –log (1.0 x 10^-7)

now i have the old school Casio calculator
http://i17.ebayimg.com/06/i/001/3b/5e/f267_1.JPG

hmm i get that but how do i punch in ^-7 on my calculator?
thanks i just found the e on my old calculator…please double check if i’m right from the pic link i put up….i pressed (shift) then (In) its placed right next to the log button

You got it its -log( 1.0 x 10^(-7))
Or if your calculator has capital E
then
-log(1.0 X 10E-7) ## Strange pattern in the calculator number sequence?

Doing some work with number sequence here is what I found.
the calculator number sequence is like this from 0 to 9

7 8 9
4 5 6
1 2 3

The catch is, when you add three consecutive numbers in the exactly opposite and flipped direction, the sum is always a constant.
check this..
741+369 = 1110
789+321= 1110
diagonally 951+159=1110
357+753=1110
even these complicated patterns..
645+465=1110
478+632=1110
421+689=1110
639+471=1110
958+152=1110
ive tried all and they remain the same..

Surprisingly odd 😛 .. any clues why ?

It happens that any line through the 5 intersects 2 numbers that add up to 10. There are 4 pairs [7,3 8,2 9,1 6,4] so as long as you do a pattern symmetrical around the 5 (or using 5 in the same place in each pattern as you have done), you are always going to get 1110 adding two lots of 3 digits. If you used 4 digit sequences you’d get 11110 and 5 digit sequences 111110 and so on… ## Is this function even,odd, or neither?

A) x sin x

B) cosx sinx

I know how to do it with a calculator, but they are forbidden on tests. So i need to know how to do this WITHOUT a calculator.

Well to check it you have to calculate f(-x) and compare it to f(x).
So, if f(x)=f(-x) => even
if f(x)=-f(x) => odd
And if none is true then it’s neither.

So for
A) f(x)=x*sinx
f(-x)=-x*sin(-x) since sin(-x)=-sinx f(-x)=-x*(-sinx) f(-x)=xsinx=f(x) => even
B) f(-x)=-sinx*cosx=-f(x) => odd