Question

find exact value of 1/cos^2(40) - 1/cot(40)

Answer 1

1/cos²40 - 1/cot²40
= 1/cos²40 - tan²40
=1/cos²40 - sin²40/cos²40

1 - sin²40
------------
cos²40

Remember the Pythagorean identity
Sin²x + Cos²x = 1
Cos²x = 1- Sin²x


cos²40
----------- = 1
cos²40

Answer 2

thanks but the cot isnt squared

Answer 3

Ahh.. I did't notice... sorry..

Answer 4

you think you could do it without the cot squared?

Answer 5

1/cos²40 - 1/cot40
= 1/cos²40 - tan40
=1/cos²40 - sin40/cos40

1 - sin40 cos40
------------
cos²40

1 - sin40
--------
cos40

I don't know what's next...

Answer 6

but to take out a cos wouldnt you have to have it on the sin and 1 this is why its confusing me

Answer 7

Maybe you should stop there... Or inputting this on the calculator will give you 0.4663.

Answer 8

it says no calculators

Answer 9

but its either 1 or 0

Answer 10

Ahh.. maybe its 1..
not sure... just a guess.

Answer 11

ok if i change the cos^2 to 1-sin^2 could anything happen with that?

Answer 12

This part?

Answer 13

at the beginning of the equation so its 1/1-sin^2(40) - tan(40)

Answer 14

You'll come up with the same thing, I guess..

Answer 15

man this is dumb alright thanks for the help i am gonna close it

Answer 16

Okay..