Finding unknown coefficients in trigonometric graphs

[Kahsi]

Problem with graphs

Hi!
I hope this is the right place to post this.

I'm having problem with this kind of problems. I hope you could explain step by step on how you're solving this. To be sure that I understand well I'm posting two examples. Both of them are from old math tests I'm reding to prepare myself for my test.

1:
y = 10sinx + csin2x
What's c?

http://home.tiscali.se/21355861/bilder/graph1.PNG

...

2:
y = 12sinx
y = 12sinx + dsinkx

What's d and k?

http://home.tiscali.se/21355861/bilder/graph2.PNG


I hope someone can explain this. Please don't just give me the answer because I want to understand it.

Thank you in advance


Edit: it should be graphs not graphes

 

[mathman]

In both cases the letters you are asking about represent constants. However, particular values for these constants have not been supplied. To graph the functions, you would need them. However some general properties can be seen by trying a few cases. In problem 1, try c>10, c=10, c<10, also negative values of the same magnitude. For problem 2, similarly for d (using 12 as the break point). I assume k is supposed to be an integer, so try different values, noting that k=2 is basically problem 1.