Answer: A=0.8767601914
First you need to find the value of cos(3) and sin(7) which happens to be cos(3)=0.9986295348A and sin(7)=0.1218693434A. So you have the numbers, then what do you do with them? Well you will want to subtract them both and find the difference between them which should be the value of A. so 0.9986295348-0.1218693434=0.8767601914 so A=0.8767601914 if you want you can simplify this...
Explanation:
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