hi, can you check if im right when trying to find the missing angle of this shape?

Attachment 20645

to work this out i did this:

inverse tan 7/11= 7.44???

is this correct? if not where am i going wrong?

thanks!

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- Jan 31st 2011, 06:26 AMandyboy179missing angle
hi, can you check if im right when trying to find the missing angle of this shape?

Attachment 20645

to work this out i did this:

inverse tan 7/11= 7.44???

is this correct? if not where am i going wrong?

thanks! - Jan 31st 2011, 06:38 AMBAdhi
how did you calculate $\displaystyle tan^{-1}(7/11)$ (and state whether radians or degrees)

- Jan 31st 2011, 06:43 AMandyboy179
on my calculator i just wrote " tan^-1 7/11= 7.44

my calculator is in degrees! - Jan 31st 2011, 06:48 AMAckbeet
Your calculator, due to the lack of parentheses, computed $\displaystyle \tan^{-1}(7)/11,$ not $\displaystyle \tan^{-1}(7/11).$ Try that again, and see what you get. This is what BAdhi was getting at, I think. Incidentally, you were right to doubt the correctness of the result. You should always have a rough idea of what a calculator is going to give you.

- Jan 31st 2011, 06:50 AMandyboy179
okay, so i nned to do $\displaystyle \tan^{-1}(7)/11,$ = 32.47??

- Jan 31st 2011, 06:54 AMAckbeet
Right answer, wrong typing. You should have

$\displaystyle \tan^{-1}(7/11)\approx 32.47^{\circ}.$ - Jan 31st 2011, 06:59 AMe^(i*pi)
Some models require the argument first. If this is the case type $\displaystyle 7 \div 11$ and then inverse tan button