Printable View

Find the exact value of sin2x. Sinx = (-4/7)

Quote: Originally Posted by jumpman23 Find the exact value of sin2x. Sinx = (-4/7) You should know from class that $\displaystyle \sin(2x)=2\sin(x)\cos(x)$. You already known sin(x). To find cos(x) you can use the info already given to draw a right triangle and solve for the missing leg needed to find cos(x).