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A trig identity 2015-10-28
From Gail:
verify sec(x) =cot(x)+tan(x)/csc(x), the csc(x) is under both the whole term cot(x) + tan(x)
Answered by Penny Nom.
A trig identity 2013-01-04
From Tehmas:
Prove sinC+sinD=2sin(C+D/2)cos(C-D/2)
Answered by Harley Weston.
A trig identity 2012-01-08
From Joe:
Prove this Trig. Identity :

((cos2θ + sinθ-1) / tanθ ) + sin2θ = cosθ

Answered by Penny Nom.
I started with Euler's identity and manipulated it 2011-11-14
From anonymous:
I started with Euler's identity and manipulated it
e^i*pi=-1
e^-i*pi=(-1)^-1
e^-i*pi=-1
e^-i*i*pi=(-1)^i
e^--pi=(-1)^i
e^pi=(-1)^i
type it in in a calculator and you get e^pi=23.1406926... and (-1)^i=0.0432139183... What did I do wrong?

Answered by Robert Dawson.
sin A/1+cos A + 1+cos A/sin A = 2cosec A 2011-10-20
From Neeraj:
sin A/1+cos A + 1+cos A/sin A = 2cosec A
Answered by Penny Nom.
Tan(x+pi)-tan(pi-x)=2tan(x). 2011-01-09
From Steven:
Verify the identity:
Tan(x+pi)-tan(pi-x)=2tan(x)

Answered by Penny Nom.
A trig identity 2010-03-27
From Anne:
Prove: (2tanx-sin2x)/2sin^2x=tanx
Answered by Penny Nom.
A trig identity 2010-03-08
From Kim:
I am having trouble proving this trig identity

(sin^2 x + 2 cos x-1) / 2+cos x - cos^2 x = 1/ (1+ sec x)

Answered by Penny Nom.
A trig identity 2010-01-24
From Natalie:
hi, i need help proving the following trig identity. i cant seem to figure out how to do it. thanks so much.
(1+sin2x)/cos2x = cos2x/(1-sin2x)

Answered by Penny Nom.
A trig identity 2010-01-21
From Alesia:
How to prove Csc(A+B) = (csc A Csc B)/ (Cot A+ Cot B)
Answered by Penny Nom.
A trig identity 2010-01-05
From Christine:
I need help with this whole paper here is one problem

csc^2x-cot^2x/1-sin^2x=sec^2x
by the ^2 i mean squared pleease

Answered by Penny Nom.
sin x / 1+ cos x = csc x - cot x 2009-11-18
From Mansi:
i need a hint on how i could prove the following identity:
sin x / 1+ cos x = csc x - cot x

Answered by Harley Weston.
A trig identity 2009-07-10
From sam:
I need to prove:

tan x (cot x + tan x) = sec2 x
(the "sec2" is "sec squared")

I am totally stuck!!
Thanks!

Answered by Stephen La Rocque and Harley Weston.
A trig identity 2009-06-30
From sumayya:
prove that sin A (1+tan A)+cos A (1+cot A)= sec A+ cosec A
Answered by Robert Dawson.
Finding an Acute Angle using Trigonometric Identities 2009-06-29
From Nazrul:
How can I find the value of A if sinA-cosA=1 , where A is an acute angle.
Answered by Stephen La Rocque.
sin x/ 1+cos x = 1-cos x/ sin x 2009-05-30
From rita:
prove: sin x/ 1+cos x = 1-cos x/ sin x
Answered by Stephen La Rocque.
Sec(2x) 2008-11-23
From Evan:
Prove that this is an identity...

sec2x = sec^2x / 2 - sec^2x

Answered by Harley Weston.
A trig Identity 2008-11-13
From Rebecca:
Question from Rebecca, a student:

How do I prove:

     1/sin@                csc@                -2sin@
________      +       ______       =    _____
1 + CSC@         1-1/sin@                 cos^@
Answered by Penny Nom.

A trig identity 2008-11-03
From Student:
verify cos(2x)=(cot(x)-tan(x))/(cot(x)+tan(x))
Answered by Penny Nom.
TRIG IDENTITIES 2008-08-17
From VINCE:
HOW DO YOU SIMPLIFY THE FOLLOWING:- 2sin3(theta)cos3(theta)? Regards
Answered by Harley Weston.
Graphing Using Double Angle Identities 2008-07-16
From Hodan:
the Question is: Describe how you could use your knowledge of Double angle formulas to sketch the graph of each function. Include a sketch with your description.A) F(x)=sin x cos x B)F(x)=2 cos(squared)x C) F(x)= tan(x) (divided) by 1-tan(squared) x
Answered by Janice Cotcher.
cos3A=-1/3 find cos6A 2008-05-15
From mike:
cos3A=-1/3 find cos6A
Answered by Penny Nom.
2 tan theta /(1 + tan^2 theta) = sin 2theta 2008-03-25
From Charmaine:
I'm having trouble on where to begin proving identities. I must prove that (2 tan theta / 1 + tan^2 theta) = sin 2theta
Answered by Penny Nom.
(1-tanx) / (1+tanx) = (1-sin2x) / cos2x 2008-02-14
From isaiah:
i'm having trouble proving 1-tanx / 1+tanx = 1-sin2x / cos2x, can anyone help me from going crazy?
Answered by Penny Nom.
A trig identity 2007-11-28
From Julia:
    sin4x              1 - cos2x
------------    x      ----------         =     tanx
1 - cos4x               cos2x

Answered by Harley Weston.
A trig identity 2007-11-10
From James:
I need to prove trig identities, and I can't figure this one out

1 + sinx - cosx         1 - cosx
-------------------- = -------------
1 + sinx + cosx         sinx

Answered by Chris Fisher.
A trig identity 2006-12-28
From Courteny:
Prove that 1 - cos 2x + sin 2x (divided by) 1 + cos 2x + sin 2x = tan x
Answered by Penny Nom.
A trig identity 2006-12-14
From Zamira:
i need help with this proof: ((cot(x)-tan(x))/ cot(x) + tan(x)) = cos (x)
Answered by Penny Nom.
Sin 2x / 1-Cos 2x = 2 Csc 2x - Tan x 2006-12-06
From Mark:
I need to prove the following:
Sin 2x / 1-Cos 2x = 2 Csc 2x - Tan x

Answered by Steve La Rocque.
tan1/2x + cot1/2x = 2cscx 2006-11-04
From Jazmin:
Prove tan1/2x + cot1/2x = 2cscx
Answered by Penny Nom.
A trig identity 2006-06-04
From Courtney:
Show that this equation is an identity: (sin x + sin 2X)/(cos x - cos 2x) = cot(x/2)
Answered by Stephen La Rocque.
A trig identity 2006-03-28
From Iqbal:
Could you please prove,

[tan(x)-sin(x)]/sin3(x)=sec(x)/[1+cos(x)]
Answered by Stephen La Rocque.

A trigonometric identity 2006-01-22
From Sarfaraz:
Prove the following trigonometric identity.
sin2x = tan2x/(1+tan2x)

Answered by Penny Nom.
A pair of trig equations 2005-12-05
From Kevin:

I am trying to solve for A and B but haven't been able to find a trig identity that will help me.

1.414 = .5cosA + cosB
.5 = .5sinA - sinB

how do I solve this?


Answered by Penny Nom.
cos(2x) = sin(3x) 2005-04-14
From A student:
Show that if x= 18 degrees, then cos2x =sin 3x. HENCE find the exact value of sin 18 degrees, and prove that cos 36 - sin 18 =1/2.
Answered by Andrei Volodin, Claude Tardif and Penny Nom.
tan55.tan65.tan75=tan85 2005-03-30
From Jesus:
My name is Jesus and Im a secondary student. Im trying to verify a trigonometric identity but I dont know how to do it.please help me!!!!!!!!!.

The identity is : tan55.tan65.tan75=tan85 (the sign (.) indicates multiplication)


Answered by Chris Fisher and Penny Nom.
A trig identity 2005-03-06
From Patrick:
im trying to verify this identity:

sin(x)+sin(5x)
-------------------- = tan(3x)
cos(x)+cos(5x)


Answered by Chris Fisher.
A trig identity 2003-11-12
From A student:
I can't prove this identity. Can you please help me?
(1-tanx)/(1+tanx)=(1-sin2x)/(cos2x)

Answered by Penny Nom.
A trig identity 2003-05-20
From Patty:
Please help with the following

1/ tanx + cotx = sinxcosx

Answered by Penny Nom.
Three proffs of a trig identity 2003-03-18
From Nadene:
Prove the identity. cos [x + (y-pi/2)] = sin (x+y)

A hint was also provided which is: "Apply cos (alpha + beta) first then within that apply cose (alpha-beta)"

Answered by Penny Nom.
A trig identity 2003-02-22
From Ron:
We have spent hours trying to solve the following identity without success. Can you give us some hints as to how it is done?

1 + tan(x) tan(2x) = tan(2x) cot(x) -1

Answered by Penny Nom.
The identity property 2002-11-07
From Stephanie:
I am a student teacher this semester in the third grade. I was looking at our math competencies and saw that we needed to teach the identity property. Is this the same as the distributive property? If not, what is it?
Answered by Penny Nom.
An identity? 2002-10-27
From Jenna:
I can't prove
 
1-sinQ     1 ---- = tanQ + --- 1+sinQ      cosQ 

Answered by Penny Nom.
An identity(?) 2002-05-02
From A student:
prove identity sin 2x/1-sinx= secx+1/secx


Answered by Paul Betts.
A trigonometric identity 2002-03-22
From Debby:
I am stuck on a problem and wondering if you can help?? It is: Prove the following:
sec2(X)+csc2(X) = sec2(X)csc2(X)

Answered by Harley Weston.
A trig identity 2001-07-27
From Jeff:
prove this identity and show steps
tan(x/2+pi/4)=secx+tanx

Answered by Harley Weston.
Trig identity crisis 2000-11-29
From Rhiannon:
I have tried many times to find the answer to these problems but I can't I am in grade 12
  1. tan(x)=csc2(x)-cot2(x)
  2. cos(x)/csc(x)-2sin(x)=tan(x)/1-tan(x)
  3. cos(x)[ tan2(x)1-1]/cos2(x)+sin2(x)=sec(x)

Answered by Harley Weston.
A trigonmetric identity 2000-05-15
From Caitlin:
My name is Caitlin and my question is from 11th grade math and I'm a student

my question is I need to solve this identity :

cos x csc x - sin x sec x = 2 cot 2x


Answered by Paul Betts.
Matrices Information 2000-05-02
From William Avery :
I am an OAC student at Governor Simcoe Secondary School in St. Catharines Ontario. Today at school we were handed an independent study project by our Finite teacher. This assignment is based on Matrices, it involves performing some simple matrix calculations, but also involves a written section. This written section asks for the following:
.
.
.

Answered by Marley Weston.
A trig identiry 2000-02-23
From Ashlee:
I am having problems doing this problem. Can you help?

Verify the identity: (1+cot2X)(1-cos2X)=2


Answered by Harley Weston.
A trig identity 2000-02-17
From Eric:

Question:
How do I solve this problem?

 sin3x   cos3x _____ - _____ = 2 sinx cosx 

Answered by Chris Fisher.
Proving a trigonometric identitiy 1999-12-17
From Ryan:
I need to figure out how to prove that sec2x + csc2x = sec2x csc2x. I am not sure where to start out with it and whether I should use reciprocal, quotient, or pythagorean.
Answered by Penny Nom.
A trig problem 1999-06-03
From Stu Barnes:
cos(theta) / 1+ sin(theta)=sec(theta)-tan(theta)

I've being having trouble with this one on my correspondance course.
Answered by Harley Weston.

Triminoes 1998-09-09
From Roxanne Hale:
I am doing an investigation about a game called triminoes (like dominoes). The game is played using triangular pieces of card. Each card has 3 numbers on it. I have to investigate the relationship between the number of trimino cards in a set and the largest number on the cards. I found;

largest no. used 0 1 2 3 4
no. of trimino cards 1 4 10 20 35

I was ginen the formula for this which is:
UN= UN - 1 + 1/2 (n + 1 ) (n+2)

UN=no. of trimino cards n= largest no.

I don't know how to get to this equation I think it has something to do with triangle numbers!
Answered by Penny Nom.

A trig identity 1996-03-11
From Azmat Hussain:
Is there an easier/another way to prove the trig identity cos(a+b) = cos(a)cos(b)-sin(a)sin(b)?
Answered by Penny Nom.
Trig identities 1995-11-30
From Azmat:
Why do we work on the two sides of a trig identity separately?
Answered by Harley Weston.
 
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