Question

I need help solving: If sin(theta)=12/13, cos >0 then what would cos(2theta) be?

Answer 1

\[\sin(2\theta)=1-2\sin^2(x)\]

Answer 2

replace \(\sin(x)\) by \(\frac{12}{13}\) and do the arithmetic

Answer 3

ok that was not what i meant to write
i meant
\[\cos(2\theta)=1-2\sin^2(x)\]

Answer 4

your only job now is to compute
\[1-\left(\frac{12}{13}\right)^2\]

Answer 5

that business about what quadrant you are in is a red herring