Please help with this identity, I feel like I am getting really close.
If you want to know where I keep getting stuck, it is at
first: if you are proving an identity, you are not allowed to work on both sides at the same time. work on one side at a time, either trying to change one side to look like the other, or changing both sides to the same thing
second: you cannot split the denominator of a fraction!!!!! (i want to put more exclamation marks, but i don't want you to think i am angry with you )
in general
i dont know how to use the forum's fraction option.
where did you got your sinX on the second side?
here is how you do it anyway,
cross multiply the first side(continued from the one that you are working) and you get sinX-sinXcosX/sinX squared, then factor the numerator, you get sinX(1-cosX). cancel the sinX and the sinX from the denominator removing its square. then you get (1-cosX)/sinX on the first side and sinX/1+cosX on the second. then from a/b=c/d equals a.d=c.b we get 1 - cosx squared = sinX squared.
thus we have proven the identity~
he meant, subtract as in write it as 1 minus cosX. of course you dont subtract it literally(i.e. perform the operation).
why cant cross multiply? im just basically following the indicated operation. anyway, that is how we were thought and it was proven nonetheless. point out exactly which part i did wrong and then we'll talk.
@sk8erboyla2004
both will arrive at the same answer anyway. look at my answer after cancelation.lol any fraction with common denominator, you can do the copy denominator rule or do what i just did. both will be correct just that the copy the denominator rule will be in the lower term.
p.s.
jhevon maybe you can help me with my geometry? im having hard time picturing the figure. http://www.mathhelpforum.com/math-he...ian-plane.html
I'm giving up on this problem. I have been working on it for about 6 hours and I cant handle it anymore. What can you suggest that will help you get better at identities, that dont involve me banging my head against a wall?
Irealise that this problem is pretty simple, but it is hard for me
if you understood until that part then good.
a/b=c/d equals a.d=c.b
its as is.
if the fractions are equal, the numerator of the first fraction times the denominator of the second fraction will always be equal to the denominator of the second fraction times the numerator of the first fraction.
i.e.
1/2 = 2/4
1 x 4 = 4
2 x 2 = 4
or
3/6 = 6/12
3 x 6 = 36
6 x 6 = 36
colored numbers are numerators.