If the 10 books are all different, we have:
• 10 ways of selecting the first book,
,• 9 ways of selecting the second book,
,• 8 ways of selecting the third book,
,• 7 ways of selecting the fourth book.
The total number of ways to arrange 4 of the 10 books is:
Answer
There are 5040 ways of arranging the books.
9. You need an exact answer. So I will give you it but I'll also give you an approximation because it might help you understand it more.
Because we know the cosine fo theta, we can evaluate the inverse cosine of -2/3 first to find theta.
= 131.81° approx.
Because 131.81° is in the second quadrant its third quadrant partner is 228.19°. Which would make the sine 0.75 approximately.
But we need an exact answer I suppose so which is this disgusting mess.... I know it looks scary but it is basically all the steps we just did but without evaluating anything.
This can be simplified using: sin(x− y) = sinxcosy−cosxsiny
To...
answer:
10. Okay. So because we have a point we can say that...
θ =
sin(θ) = +sin()
11. arcsin(-0.37) = = -21.72°+2kπ or 201.72°+2kπ approx. where k has to be an integer
answer: idk if you want one or more solutions so I gave you them all.
12. arccos(-√3/2) =
Remember that "k" must be an integer.
answer: 5π/6