You are Here: Home >< Maths

C2 TRIG Watch

1. Question 20 in the mixed exercise of trig identities...

The diagram shows part of a curve with equation f(x) = 1+2sin(px+q) p and q being positive constants and q < 90.

Give than the coordinates of A and C are (0,2) and (45,0) respectively:

Calculate value of q - DONE

show that p = 4

Not sure how to do this one.. I get so far as...

sin(45p +30) = -30

But when I looked up the answer it should be

sin (45p+30) = 210

I now p is supposed to be postive - but just not sure where the 210 comes from because i get -30.....

This is the link to the question if you need the full thing...

2. Remember sin has two solutions (by this I mean the other solutions are just +/- 360 degrees). Say one is x. The other one is then 180-x. In your case 180--30=210 (degrees)
3. (Original post by christinajane)
Question 20 in the mixed exercise of trig identities...

This is the link to the question if you need the full thing...

Better fix it !!
4. (Original post by christinajane)
Question 20 in the mixed exercise of trig identities...

The diagram shows part of a curve with equation f(x) = 1+2sin(px+q) p and q being positive constants and q < 90.

Give than the coordinates of A and C are (0,2) and (45,0) respectively:

Calculate value of q - DONE

show that p = 4

Not sure how to do this one.. I get so far as...

sin(45p +30) = -30

But when I looked up the answer it should be

sin (45p+30) = 210

I now p is supposed to be postive - but just not sure where the 210 comes from because i get -30.....

This is the link to the question if you need the full thing...

If you draw the sin graph for -180<x<180, you can see that there are 4 different values x could take when y=-0.5 with the lowest, positive value being 210. Therefore that is the value you take and put in the equation
5. (Original post by NNB_Herath)
Better fix it !!
oops sorry!

https://0e90d90be05fe2865012661b731d...apter%2010.pdf
6. (Original post by Math12345)
Remember sin has two solutions (by this I mean the other solutions are just +/- 360 degrees). Say one is x. The other one is then 180-x. In your case 180--30=210 (degrees)
Ahhh ok that makes sense! thanks For that.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 15, 2016
Today on TSR

How to stand out in an Oxbridge interview

What makes you memorable?

A pregnant woman visits me every night

Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

How to use LaTex

Writing equations the easy way

Study habits of A* students

Top tips from students who have already aced their exams

Chat with other maths applicants

Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE