# trigonometry

posted by .

{1/(sec x - 1)} - {1/(sec x +1)} = 2 cot^2 x

solve using identities?

• trigonometry -

Hey, I did this for you long ago.

• trigonometry -

Twice in fact

• trigonometry -

copy again
sin a cos b + cos a sin b = sin (a+b)
so sin (7t)

1/(1/cos x -1) - 1/(cos x +1)

cos x/(1 - cos x) - cos x/(1+cos x)

[cos x(1+cos x) - cos x(1-cos x)]/(1-cos^2 x)

[ cos x + cos^2x - cos x +cos^2 x]/sin^2x

2 cos^2 x/sin^2 x

2 cot^2 x

• trigonometry -

ohh, i didn't realize! thankyou :)

• trigonometry -

Please check before repeating posts. Some other teacher might have done it all over again.

• trigonometry -

okay!

## Similar Questions

1. ### Trigonometry

I don't understand how I'm supposed set the problem up or what theta is... Use the given function value(s), and trigonometric identities (including the cofunction identities), to find the indicated trigonometric functions. sec theta …
2. ### Math - Trigonometry

Verify the following: 1. cos x/(1-sinx)= sec x + tan x 2. (tanx+1)^2=sec^2x + 2tan x 3. csc x = )cot x + tan x)/sec x 4. sin2x - cot x = -cotxcos2x
3. ### Math

Prove Trig. Identities 1. sec è (sec è - cos è)= tan^2 è 2. tan^2 è (1 + cot^2 è) = sec^2 è
4. ### trigonometry repost

Reduce (csc^2 x - sec^2 X) to an expression containing only tan x. (is this correct?
5. ### trigonometry

Use identities to simplify each expression. 1) (sin2t) (cos5t) + (cos2t) (sin5t) 2) {1/(sec x - 1)} - {1/(sec x +1)} = 2 cot^2 x
6. ### Trigonometry

Verify/Solve the identities. 1.) SIN^1/2 X COS X-SIN^5/2 X COS X 2.) Long problem, but it's fun to solve! SEC^6 X(SEC X TAN X)-SEC^4 X(SEC X TAN X)
7. ### Trigonometry

Verify the identities. 1.) SIN[(π/2)-X]/COS[(π/2)-X]=COT X 2.) SEC(-X)/CSC(-X)= -TAN X 3.) (1 + SIN Y)[1 + SIN(-Y)]= COS²Y 4.) 1 + CSC(-θ)/COS(-θ) + COT(-θ)= SEC θ (Note: Just relax through verifying/solving …
8. ### Trigonometry

Simplify each expression using the fundamental identities. 1. Sec x csc x / sec^2x+csc^2x 2. Sec x + tan x / sec x + tan x - cos x
9. ### Trig verifying identities

I am having trouble with this problem. sec^2(pi/2-x)-1= cot ^2x I got : By cofunction identity sec(90 degrees - x) = csc x secx csc-1 = cot^2x Then split sec x and csc-1 into two fractions and multiplied both numerator and denominators …