# Trig doubtWatch

This discussion is closed.
Thread starter 14 years ago
#1
The book has a s a solution for 0<=A<=180

sinA = 0 > A = 90ยบ

Surely that is wrong. Or is it my brain that's seized up altogether?

sinA = 0 > A = 0

And so i think the answer within the range should be 0ยบ and not 90ยบ

Help...

jorge
0
14 years ago
#2
(Original post by Jorge)
The book has as a solution for 0<=A<=180

sinA = 0 > A = 90ยบ

Surely that is wrong. Or is it my brain that's seized up altogether?

sinA = 0 > A = 0

And so i think the answer within the range should be 0ยบ and not 90ยบ

Help...

jorge
I don't think I have the question grasped correctly! Can you type it in verbatim?

Aitch
0
14 years ago
#3
...and the given answer?

Aitch
0
Thread starter 14 years ago
#4
(Original post by Aitch)
I don't think I have the question grasped correctly! Can you type it in verbatim?

Aitch

It's not so much the question itself. It's the answer.

If you end up with sinA = 0

what is the value of A between 0ยบ and 180ยบ.

The book says 90ยบ!

jorge
0
14 years ago
#5
(Original post by Jorge)
It's not so much the question itself. It's the answer.

If you end up with sinA = 0

what is the value of A between 0ยบ and 180ยบ.

The book says 90ยบ!

jorge
Nope

0 or 180

Aitch
0
14 years ago
#6
(Original post by Aitch)
Nope

0 or 180

Aitch
Are you sure sure sure you haven't got a sin for a cos somewhere?

Aitch
0
14 years ago
#7
have you tried substituting their answer into the start to see if the working has gone wrong
0
Thread starter 14 years ago
#8
(Original post by Aitch)
Are you sure sure sure you haven't got a sin for a cos somewhere?

Aitch
I am not talking about my workings or answer.

It is the book itself that came up with the answer

sinA = 0 > A = 90ยบ
0
14 years ago
#9
(Original post by Jorge)
I am not talking about my workings or answer.

It is the book itself that came up with the answer
Ah!

I'm with you now. I hadn't realised that this bit was a direct quote.

Aitch
0
Thread starter 14 years ago
#10
Therefore ?....

The book is wrong. Right?

jorge
0
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