# I'm friendly with sin

I can scare many people, I'm quite friendly with sin
In fact, he and I are practically twins
I'm the opposite of dry, if you'll pardon my French
Want a loan? You might need my help

Who am I?

Are you...

cosine

I can scare many people, I'm quite friendly with sin
In fact, he and I are practically twins

Referencing how math can scare people, and sin/cosine

I'm the opposite of dry, if you'll pardon my French

Referring to sec, the French word for dry. (Thanks, Mike M.!)

Want a loan? You might need my help

Wordplay on cosine with cosign.

• Yes. :-) Look up the word for "dry", not "wet". When you figure out that clue, I'll accept the answer.
– user17947
May 14, 2016 at 8:35
• I'm new here. Are we allowed to help? I think I know what it is. May 14, 2016 at 9:54
• @MikeM. Welcome to Puzzling! Yes of course May 14, 2016 at 10:16
• @Xylius Thank you. TBH, I'm just new to participating. I joined a while ago. May 14, 2016 at 10:21
• @Josh I believe the OP is referring to sec. It means dry in French, and secant - abbreviated sec - is the reciprocal of cosine. May 14, 2016 at 10:21

cos, the mathematical (trigonometric) function that's the ratio of the adjacent side of a right triangle to its hypotenuse.

friendly with sin. In fact, we're practically twins

You mean $\sin$, the ratio of the triangle's opposite to its hypotenuse. They're twins in the sense that $\sin(x+\frac{\pi}{2}) = \cos(x)$

I'm the opposite of dry, if you'll pardon my French

Dry means "sec" in French, which is the multiplicative inverse of cos.

Want a loan? You might need my help

I'm not sure about this one, but I'm guessing that has to do with how the money you have increases when you get a loan, but it's bound to decrease after some time when you pay it, similar to how the value of the cos function goes from 1 to 0 again with time.

• Clever.  Unfortunately, this is basically the same as the other answer, which was posted 2½ hours before yours.  Also, the riddle says, “I’m the opposite of dry”, but you’ve presented an argument why sin is the opposite of dry. May 14, 2016 at 12:40
• -1 because it's same as the other answer. May 14, 2016 at 15:48
• You say that you managed to explain the 3rd hint before him. But it was already explained in the comment section of that answer. And the more important thing is that you should check if you are duplicating any existing answer before posting another answer. May 14, 2016 at 16:14
• @manshu that is completely unjustified. This answer is not the same. He made different explanations and different opinions. May 14, 2016 at 19:24
• @AimanAl-Eryani Looks to me like Mike M. was 2 minutes faster. May 14, 2016 at 23:38