Question

What is cos 2x when tan= -3/4 ?

Answer 1

\[\cos(2x)=2\cos^2(x)-1\]
what you need to answer is "if \(\tan(x)=-\frac{3}{4}\) then what is \(\cos(x)\) ?"

Answer 2

4/5

Answer 3

yes indeed
your only job now is to compute
\[2\times(\frac{4}{5})^2-1\]

Answer 4

33/25 is that the answer ?

Answer 5

Is the answer 7/25?

Answer 6

yes

Answer 7

to the second one, not the first one

Answer 8

One more question what is the sin 2x when tan = -3/4
2/1 x -3/5 x 4/5 = -24/25
I got that is it right?