# Need help before final

• May 5th 2009, 06:55 PM
coasterguy
Need help before final
I'm trying to figure out how to do these, but I'm lost:

Quote:

Suppose A is in Quadrant IV and tan A = B. Write each one of the following values in terms of B.

cotA=
secA=
cosA=
sinA=
cot(90°-A)=
sin(2A)=

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Quote:

Find all solutions Θ, 0° <= Θ < 360°
cos(3Θ + 15°) = 1/2

Thanks!
• May 5th 2009, 07:06 PM
Shyam
Quote:

Originally Posted by coasterguy
I'm trying to figure out how to do these, but I'm lost:

Thanks!

$\cot A = \frac{1}
{{\tan A}} = \frac{1}
{B} \hfill \\$

$\sec A = \sqrt {1 + \tan ^2 A} \hfill \\$

$\cos A = \frac{1}
{{\sec A}} \hfill \\$

Finish it all.
• May 5th 2009, 07:11 PM
Shyam
Quote:

Originally Posted by coasterguy

cos(3Θ + 15°) = 1/2

Thanks!

$\cos \left( {3\theta + 15^\circ } \right) = \frac{1}
{2} \hfill \\$

$3\theta + 15^\circ = 60^\circ \hfill \\$

finish it.

${\text{OR}} \hfill \\$

$3\theta + 15^\circ = 300^\circ \hfill \\$

finish it.