trapezoid rule

[jillmb]

Use the Trapezoidal Rule to approximate the given integral with the specified value of n. (Round your answers to six decimal places.)



n = 8
delta x = 1/2

I feel like this should be super straight forward, but I can't seem to get to the correct answer (-0.495333)

I start with this


So, then, plugging it into the function


When I plug this into my calculator I get 1.627141. I know the final answer is -0.495333, but I can't figure out what I'm doing wrong.

Any help is greatly appreciated! Thank you!

 

[Deleted member 4993]

Use the Trapezoidal Rule to approximate the given integral with the specified value of n. (Round your answers to six decimal places.)

View attachment 22744

n = 8
delta x = 1/2

I feel like this should be super straight forward, but I can't seem to get to the correct answer (-0.495333)

I start with this
View attachment 22745

So, then, plugging it into the function
View attachment 22747

When I plug this into my calculator I get 1.627141. I know the final answer is -0.495333, but I can't figure out what I'm doing wrong.

Any help is greatly appreciated! Thank you!

Did you make sure that your calculator is in radian mode?

 

[jillmb]

Did you make sure that your calculator is in radian mode?

Yes, it's in radian mode.

 

[jillmb]

Yes, it's in radian mode.

Oops, I was using desmos for that (usually I use my TI-83, which is definitely set to radians) and I realized it was not set to radians. What an easy solution. Thank you.