+501 In right triangle $ABC$ with $\angle B = 90^\circ$, we have $\sin A = 2\cos A$. What is $\cos A$?
+2407 let's draw a triangle, with the legs, 1 and 2.
So th hypotenues is sqrt(5)
Sine = 2/sqrt(5)
Cos = 1/sqrt(5)
=^._.^=
+1694 sinA = 2(cosA)
sin(A) / cos(A) = tan(A)
tan(A) = 2 ∠A = 63.43494882º
cos(A) = 0.447213595
