Question

Is the answer 1/4 ?
The limit as x approaches pi/2 of (1-sinx) / (1+cos2x)

Answer 1

Is this your question:
\[\lim_{x \rightarrow \frac{\pi}{2}}\frac{1-sinx}{1+\cos^2x}\]

Answer 2

Could also be \[\cos 2x\]

Answer 3

the bottom is 1+cos(2x)

Answer 4

Have you tried plugging in values?

Answer 5

I tried but it says to use l'Hopital's Rule so I did and I got 1/4 I'm not sure if its right though

Answer 6

Wouldn't it be -1/4?

Answer 7

Because the derivative of cos2x is -2sin2x

Answer 8

yeah and then i took the derivative again and got 4cos(pi) because when you plug in pi/2 you get 2pi/2 so the 2's cancel out don't they ?

Answer 9

When using L'hopitals don't we just take the derivative once?

Answer 10

No we can take it more than once if we have to. Well, at least that's what my teacher told us

Answer 11

No, it's actually just once.

Answer 12

It is ???

Answer 13

Wait, nevermind sorry, you were right

Answer 14

Sorry for wasting your time, but yea your answer is right :)

Answer 15

So is the answer 1/4 or -1/4

Answer 16

1/4

Answer 17

Okay thank you very much for your help :)

Answer 18

Yup :)