Posted by **Shym** on Sunday, June 3, 2007 at 4:29am.

Hi, can someone give me the answer to this question:

secA-tanA=1/4. Find cosA

I got: CosA=4(1-sinA) Is my answer good?

Now multply each side by (1+sinA)

CosA(1+sinA)=4 cos^2 A

CosA=1/4 (1+sinA)

16(1-sinA)=1+sinA

15=17SinA

So you have sinA, now find Cos A from your equation you originally solved.

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