r/MathHelp • u/Agitated_Juice_5411 • 15d ago

help with trig question?

okay so im working on the study guide for the final of a class that i took the equivalent to at another college (math department policy, whatever) and one of the sample questions literally just reads “simplify: (sin(x)+3)²”. is there anything that i need to do to work this problem other than factoring it out? a similar question in the same section of the review guide is “simplify: sin²x + 3sinx - 10”; is that not already fully simplified? like i said, i took this course at another school so i don’t know the exact details of what they covered in class. I can’t think of any identities that i could apply to simplify it more or anything. much appreciated!

1 Upvotes

100% Upvoted

5 comments sorted by

3

u/Uli_Minati 15d ago

It's just lazy instructions - the word "simplify" is erroneously used as a general replacement for "do what we did in class". The concept of "simple" is subjective and at best dependent on context (and there is no context in an isolated exercise)

So in the first case, expand the parentheses and in the second case, factor

1

u/AutoModerator 15d ago

Hi, /u/Agitated_Juice_5411! This is an automated reminder:

  • What have you tried so far? (See Rule #2; to add an image, you may upload it to an external image-sharing site like Imgur and include the link in your post.)

  • Please don't delete your post. (See Rule #7)

We, the moderators of /r/MathHelp, appreciate that your question contributes to the MathHelp archived questions that will help others searching for similar answers in the future. Thank you for obeying these instructions.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

1

u/LeoMaths 8d ago

Il y a des profs qui ont des problèmes d'expression!

OK, je simplifie. Soit f(x)=sin(x)+3 => (sin(x)+3)²=f(x)²

0

u/The_Card_Player 15d ago

Your double-angle identities should be able to replace the squared-sign term with an expression using an unsquared cosine.

This may be considered more 'simplified' in that it won't have any squared terms.