Math Is Fun Forum

Anil Kumar

Member

Registered: 2008-09-21

Posts: 1

Trignometry formula

I want to submit a trignometry formula requiring a proof but this space would not allow me to either write the formula in the proper way or to copy and paste it from somewhere else. How do I go about doing this.

The trig formual I want proof of is as follows:

cos2x/(1+3sinx-4sin2x)=(1+sinx)/(1+4sinx)

Note that the cos2x in the numerator on the LHS should be cos squared x and 4sin2x in the denominator should be 4sin squared x. Unfortunately I can't express them as such here.

careless25

Real Member

Registered: 2008-07-24

Posts: 560

Re: Trignometry formula

What do u mean that the space wouldnt allow u?
Have u tried using LaTeX to post it?

Heres a couple links to get u started:

http://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/
or
http://www.mathisfunforum.com/viewtopic.php?id=4397

Last edited by careless25 (2008-09-22 10:10:30)

azlan

Member

Registered: 2008-12-15

Posts: 0

Re: Trignometry formula

submit me the formulas of algebraic expressions

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 46,190

Re: Trignometry formula

azlan,
Here they are!

---

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

cregstephen

Member

Registered: 2008-12-30

Posts: 6

Re: Trignometry formula

How can I slove this problem using Trignomentry
Two cars started from the same point, at 5 am, traveling in opposite directions at 40 and 50 mph respectively. At what time will they be 450 miles apart?

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Trignometry formula

Trigonometry can be avoided in this question.
(It would be needed if the cars weren't going directly away from each other, but they are so it isn't.)

One is travelling at 50 mph and the other is going at 40 mph, so in all they are going 90 mph away from each other.

Therefore they will be 450 miles apart in 450/90 = 5 hours.

---

Why did the vector cross the road?
It wanted to be normal.