Search found 16 matches

Fri Sep 16, 2011 10:25 pm
Forum: Trigonometry
Topic: how many solns does 5sinx = 2 have on 0 < x < 4pi ?
Replies: 1
Views: 3402

how many solns does 5sinx = 2 have on 0 < x < 4pi ?

How many solutions are there to the equation 5sinx=2 for the domain 0<x<4pi?
(5sinx)/5=2/5
sinx=2/3
sin-1(2/5)=23.5781

So does this mean there is only one solution to this equation?
If not, how do I find the other answers?
Sun Sep 11, 2011 3:38 pm
Forum: Intermediate Algebra
Topic: exponential function problem
Replies: 2
Views: 2959

exponential function problem

Carbon-14 is present in all living things. When a living thing dies, the amount of isotope at that time starts to decay. The function for radioactive decay is R(t)=R 0 (1/2) t/h , where R is the radioactivity/gram of carbon-14 at time t after death, R 0 is the radioactivity/gram of carbon at the tim...
Sun Sep 04, 2011 8:38 pm
Forum: Trigonometry
Topic: trig identity problem: (sinx + tanx) / (1 + cosx) = tanx
Replies: 1
Views: 3756

trig identity problem: (sinx + tanx) / (1 + cosx) = tanx

(sinx+tanx)/(1+cosx)=tanx

So far I have,
L.S
(sinx+sinx/cosx)/(1+cosx)
[(sinxcosx+sinx)/(cosx)]/(1+cosx)
(sinxcosx+sinx)/(cosx) * 1/(1+cosx)
(sinxcosx+sinx)/(cosx+cos^2x)
...and now I'm stuck.

Could someone help me solve this and point out what I did wrong?
Thanks
Fri Aug 26, 2011 2:22 pm
Forum: Intermediate Algebra
Topic: composition of functions problem
Replies: 2
Views: 2095

Re: composition of functions problem

Fri Aug 26, 2011 2:56 am
Forum: Intermediate Algebra
Topic: composition of functions problem
Replies: 2
Views: 2095

composition of functions problem

Given that the graph of y=f(x)---> http://imageshack.us/photo/my-images/825/img0305vg.jpg/ and the functions g(x)=2x+1, h(x)=-x+3 and k(x)=(g o f o h)(x), evaluate k(5). I'm not sure how to solve this problem :confused: so it would help of someone explained how to do this in steps. So far I have: k(...
Sat Aug 13, 2011 1:06 am
Forum: Intermediate Algebra
Topic: Word problem on rates of change
Replies: 4
Views: 2409

Re: Word problem on rates of change

Oh, so the formula would be 6s2.

I ended up getting the right answer, thanks for the help.
Fri Aug 12, 2011 3:42 pm
Forum: Intermediate Algebra
Topic: Word problem on rates of change
Replies: 4
Views: 2409

Re: Word problem on rates of change

Well so far, I've learned to find instantaneous rates of change by setting up a table with intervals of numbers that approach x in (x,y). Using these intervals I'd then substitute the numbers into the model's equation and find change in f(x)/change in x. But for this problem they do not give me an e...
Fri Aug 12, 2011 1:38 am
Forum: Intermediate Algebra
Topic: Word problem on rates of change
Replies: 4
Views: 2409

Word problem on rates of change

Q) A crystal in the shape of a cube is growing in a test tube. Estimate the rate at which the surface area is changing with respect to the side length when the side length of the crystal is 3cm. This question is from a lesson based on instantaneous rates, rate of change, etc. I don't really understa...
Fri Aug 05, 2011 10:44 pm
Forum: Trigonometry
Topic: exact value of sin(5pi/6-2pi)?
Replies: 1
Views: 3206

exact value of sin(5pi/6-2pi)?

I'm not sure if I'm suppossed to find the value of 5pi/6 (which is 1/2) and then subtract 2pi from it. Or is it sin(5pi/6)-sin(2pi)? Also, can anyone tell me how to figure out the equation of this tangent? I think the answer is tan(x-pi/4)-1, but I'm not sure. Graph is in link below. http://imagesha...
Fri Aug 05, 2011 1:21 am
Forum: Trigonometry
Topic: tanx=-4.25
Replies: 4
Views: 2296

Re: tanx=-4.25

Hey guys it turned out I did have to do tan-14.25 but without the negative sign -_-
So the reference angle would be 1.34 and then i was able to find the other values.

Thanks for the help