#Derivatives
15 messages · Page 1 of 1 (latest)
- Ask your question and show the work you've done so far. If you've posted a screenshot of a question, specify which part you need help with.
- Wait patiently for a helper to come along.
- Once someone helps you, say thank you and close the thread with:
+close - Feel free to nominate the person for helper of the week in #helper-nominations
- Do not ping the mods, unless someone is breaking the rules.
- If you're happy with the help you got here, and the server overall, you can contribute financially as well:
1-cos3x/cos³x= cos³x-4cos³x+3cosx/cos³x = 3sec²x-3 = 3(tan²x)
Rooting it would make it √3 tanx
sin-1√3 tanx = √3sec²x/√1-3tan²x
but there's no option showing it
And if I further simplify it, it becomes at most
√3sec²x/√(3(cos²x-sin²x)/3cos²x)= √3secx/√cos2x
Yet no options resemble it

What they want you to do here is take sine of both sides first. Then:
sin(y) = √(1 - cos(3x)/cos(x)^3)
Then, as cos(3x) = 4cos(x)^3 - 3cos(x):
sin(y) = √(1 - 4 + 3/cos(x)^2)
You can do the rest.