Question

@darkknight

Answer 1

step 1: get like terms on one side of the equation, you have 9cos^-1(x)
and 7cos^-1(x).
Move those 2 to one side, and have pi on the other

Answer 2

2cos^-1 x = pi

Answer 3

Yes, so far so good, divide both sides by 2
\[\cos ^{-1}(x)=\pi/2\]

what are we going to do next?

Answer 4

1/cosx = pi/2
cosx = 2/pi ?

Answer 5

Thats not actually how it works
\[\cos ^{-1}(x)\] doesnt equal
\[1/\cos(x)\]
What we want to do is take the cos of both sides, cos and cos^-1 (inverse cos) cancel each other out


\[\cos(cos ^{-1}(x))=\cos(pi/2)\]

Answer 6

ohohohohohoh
so x = cos(pi/2), which is 0?

Answer 7

yep, well done

Answer 8

thank youuuuuuuuuuuuuuu <3 xd

Answer 9

yw