n***r
发帖数: 12 | 1 Eliminate f, q from the equations:
tan(q)+tan(f) =a
sec(q)+sec(f) =b
csc(q)+csc(f) =c
and show that, if b and c are of the same sign, then bc > 2a. | n***r
发帖数: 12 | | X****r
发帖数: 3557 | 3 Don't have time, but when I was in high school this kind of problem
can usually be solved by brute force, i.e.
let tan(q/2) = x and tan(f/2) = y, then all three equations can be
expressed in x and y, which would be much easier to work with.
【在 n***r 的大作中提到】
: 自顶一下，那位大侠出手？
| n***r
发帖数: 12 | 4 谢谢 Xentar，试了一下， 还是解不出来。文科生的苦恼。。。 | t*******t
发帖数: 1656 | 5 looks like math tutoring service is in high demand. Is there any Web-based
business for this market?
【在 n***r 的大作中提到】
: Eliminate f, q from the equations:
: tan(q)+tan(f) =a
: sec(q)+sec(f) =b
: csc(q)+csc(f) =c
: and show that, if b and c are of the same sign, then bc > 2a.
| v****a
发帖数: 546 | 6 这种题是我们当年初三的题吧，可是现在我都忘记sec()和csc()了，懒得去查了
【在 n***r 的大作中提到】
: Eliminate f, q from the equations:
: tan(q)+tan(f) =a
: sec(q)+sec(f) =b
: csc(q)+csc(f) =c
: and show that, if b and c are of the same sign, then bc > 2a.
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