How can I prove (cos 3x - Cos 7x) / (Sin 3x + Sin 7x) = Tan 2x?

  • Thread starter powp
  • Start date
In summary, when not getting expected results, it is important to carefully analyze and troubleshoot the experiment. To improve experimental design, identify flaws and consult with experts. The right techniques depend on the experiment and consulting with experts can help ensure validity. If results do not support the hypothesis, consider alternative explanations and consult with experts. Negative results can also be valuable in contributing to understanding.
  • #1
powp
91
0
Hello

I have to prove that

(cos 3x - Cos 7x) / (Sin 3x + Sin 7x) = Tan 2x

So this is what I am doing

-2 Sin (3x + 7x)/2 Sin (3x-7x)/2
--------------------------------
2 Sin (3x + 7x)/2 Cos (3x-7x)/2

-2 Sin 5x Sin -2x
-----------------
2 Sin 5x Cos -2x

Sin 2x
-------
-cos 2x

Which equals -Tan 2x. What am i doing wrong??

Thanks
 
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  • #2
-2 Sin 5x Sin -2x
-----------------
2 Sin 5x Cos -2x

Sin 2x
-------
-cos 2x

Cos(-2x)=Cos(2x)
Then i believe everything is ok.
 
  • #3
Thanks for your help.
 

FAQ: How can I prove (cos 3x - Cos 7x) / (Sin 3x + Sin 7x) = Tan 2x?

Why am I not getting the results I expected?

There could be a variety of reasons for not getting the expected results. It could be due to experimental error, faulty equipment, or incorrect methodology. It is important to carefully analyze and troubleshoot the steps and variables of the experiment to determine the cause of the unexpected results.

How can I improve my experimental design?

To improve your experimental design, it is important to first identify any flaws or weaknesses in the current design. This could include inadequate sample size, lack of control group, or confounding variables. Consult with other scientists or experts in the field for suggestions and make necessary adjustments to the design.

Am I using the right techniques?

The appropriateness of techniques used will depend on the specific experiment and research question. It is important to carefully consider the advantages and limitations of each technique and choose the most suitable one for your experiment. Consult with other scientists or experts in the field for advice if needed.

How can I ensure the validity of my results?

To ensure validity, it is important to use reliable and accurate methods, carefully control variables, and have a sufficient sample size. It is also important to properly analyze and interpret the data, and consider any potential biases or limitations. Replicating the experiment and obtaining consistent results can also increase the validity of the findings.

What should I do if my results do not support my hypothesis?

If your results do not support your hypothesis, it is important to re-evaluate the hypothesis and consider alternative explanations. It could also be helpful to consult with other scientists or experts in the field to get their perspective. Remember that negative results can also be valuable and contribute to the overall understanding of a topic.

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