#1

I'm studying for a pre-calc test, and I have a practice problem thats completely stumped me, for any of the math geniuses out there, can you guys figure this one out? I have to verify that the following is a trigonometric identity:

[(cos x + 1)(tan x + sec x)]/(sec x + 1) = sin x + 1

Thanks so much!

Edit: to make it clearer to the human eye, I will write it like this as well -

sec x + 1

[(cos x + 1)(tan x + sec x)]/(sec x + 1) = sin x + 1

Thanks so much!

Edit: to make it clearer to the human eye, I will write it like this as well -

__(cos x + 1)(tan x + sec x)__= sin x + 1sec x + 1

*Last edited by nirvana4lf at Jan 15, 2007,*

#2

Geez I rememeber trig iden's. Haha tough luck i cant help ya, Im in Calculus now and I can worry about that kinda stuff.

#3

well lets see if i can help. i may not be able to but i'll send what i get anyway

#4

well lets see if i can help. i may not be able to but i'll send what i get anyway

thanks so much

#5

get the Sec x +1 out of the denominator so it will look like :

(cos x + 1)(tan x + sec x) = (sinx +1)(sec x +1)

then multiply it out I reckon that you have to solve in terms of Sec, Cos, Tan, or Sin.

(cos x + 1)(tan x + sec x) = (sinx +1)(sec x +1)

then multiply it out I reckon that you have to solve in terms of Sec, Cos, Tan, or Sin.

#6

get the Sec x +1 out of the denominator so it will look like :

(cos x + 1)(tan x + sec x) = (sinx +1)(sec x +1)

then multiply it out I reckon that you have to solve in terms of Sec, Cos, Tan, or Sin.

when verifying, you cant work on both sides. only one side, and thats gonna be the more complex side. so i cant do that.

#7

well thats the same as (cosx+1)/secx+1)*(tanx+secx)/secx+1) do you see that?

#8

well thats the same as (cosx+1)/secx+1)*(tanx+secx)/secx+1) do you see that?

no, because thats like saying (4*4)/2 is the same as (4/2)*(4/2) when in fact that first is 8 and the second is 4. when multiplying fractions, the denominators multiply as well.

#9

sorry that i cant write the whole thing out, but i think maverick is wrong. you dont touch the simple side while solving identities. because sec x is equal to 1/cos x, you can plug that in for all sec x's. i believe a lot of stuff cancels out when you do that. if it doesnt, just play around with the identities of the trig functions in the problem (sinx/cosx=tanx, etc.) good luck.

#10

if all else fails convert EVERYTHING to sines and cosines

#11

sorry that i cant write the whole thing out, but i think maverick is wrong. you dont touch the simple side while solving identities. because sec x is equal to 1/cos x, you can plug that in for all sec x's. i believe a lot of stuff cancels out when you do that. if it doesnt, just play around with the identities of the trig functions in the problem (sinx/cosx=tanx, etc.) good luck.

i have been. the best i get when simplifying is the following:

__(cos x)(sin x) + cos x + sin x + 1__

1 + cos x

#12

I'm trying to work it out for you in paint, give me 5 ;]

#13

damn it i have a precal exam tommorow.... havent studied it at all

#14

damn it i have a precal exam tommorow.... havent studied it at all

me too. well i studied for like 5 minutes and i came across this and i was like fu

**ck.**

#15

Nevermind Someone Figured It Out For Me!

#16

Trigonometric identities are fun.

#17

#18

Thanks, what program did you use to make that?

#19

I typed it up quickly in MS Word (using the Equation Editor 3.0). I think it's quick and easy to use (compared to some other editors I've tried). Then I copied the object into paint, and saved it as a .bmp, uploaded it to my server space here at uni, and referenced the link for the image tags.

*nod*

*nod*