[SIZE=4]If A=sin(-1)x, where x>0 sin(-1)x means the shift sin in the calulator of angle x

Two part question

a)show that cosA=squareroot of 1-x^2

b)find expressions in terms of x for cosecA and cos2A[/SIZE]

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- May 23rd 2006, 01:21 AMkingkaisai2Trigonometry question
[SIZE=4]If A=sin(-1)x, where x>0 sin(-1)x means the shift sin in the calulator of angle x

Two part question

a)show that cosA=squareroot of 1-x^2

b)find expressions in terms of x for cosecA and cos2A[/SIZE] - May 23rd 2006, 02:41 AMCaptainBlackQuote:

Originally Posted by**kingkaisai2**

If:

then:

but:

,

so:

.

Rearranging gives:

Now as , , and so , so we

want the positive square root in the last equation so:

RonL - May 23rd 2006, 02:46 AMCaptainBlackQuote:

Originally Posted by**kingkaisai2**

RonL