<p>I DONT UNDERSTAND HOW TO SOLVE THIS.
Given cosx=5√34/34 find the value of sin2x</p>
<p>Find x using the inverse cosine function. Multiply that value by 2 and find the sine of it.</p>
<p>Since you have 5sqrt(34)/34 that can also be expressed as 5/sqrt(34)
which means that it’s a 5-3-sqrt(34) right triangle since 34 - 5^2 = 9.
sin2x = 2<em>sinx</em>cosx
sin2x = 2(5sqrt(34)/34)(3sqrt(34)/34)
and simplify.</p>
<p>You should have learned that in Algebra 2 and then skipped Pre-Calculus. Pre-Calculus courses ought to be abolished.</p>
<p>I skipped Algebra 2 and did fine in Precalc.</p>