Question 1073681
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<pre>
Since you need to verify only, I will be short.


sin(A + B) = {{{(3/5)*(5/13) + (4/5)*(12/13)}}} = {{{15/65 + 48/65}}} = {{{63/65}}}


cos(A + B) = {{{(4/5)*(5/13) - (3/5)*(12/13)}}} = {{{20/65 - 36/65}}} = {{{-16/65}}}


tan(A + B) = {{{-63/16}}}.
</pre>

If you want more details, see the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/Trigonometry-basics/Calculating-trigonometric-functions-of-angles.lesson>Calculating trigonometric functions of angles</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/Trigonometry-basics/Selected-problems-from-the-archive-on-calculating-trig-functions-of-angles.lesson>Advanced problems on calculating trigonometric functions of angles</A>

in this site.


Also, you have this free of charge online textbook in ALGEBRA-II in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-II - YOUR ONLINE TEXTBOOK</A>.


The referred lessons are the part of this online textbook under the topic "<U>Trigonometry: Solved problems</U>". 



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Comment from student: I did have it correct! Thank you so much!
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<U>My response</U>:  I am glad to hear it !


I am glad for myself too !!