Melody

@@ End of Day Wrap   Sat 25/7/15     Sydney, Australia Time   7:25pm   ♪ ♫

WELL, AFTER ALMOST 9 FULL DAYS THE FORUM IS BACK UP !!!     

It was caused by the war of the popcorn!    TitaniumRome said that there was a truce but HE broke our forum!  His was the last post and it was sitting at the front of the queue for 8 days so that we could all see is mischeif!

I do not understand your answer Heureka :/

3x,5x-4,5x are first 3 consecutive terms of an arithmetic sequence . What is its 10th term?

d=5x-(5x-4) = 4

so

5x-4-3x=4

2x=8

x=4

so

a=3*4=12     d=4

Tn=a+(n-1)d

T10 = 12+9*4 = 48

A posh function is like a a ball.  A functions where really posh people hang out.   

I suspect you really want to know what a cosh fuction is:         

$$\cosh(x) = \frac{e^x+e^{-x}}{2}$$             

If you have you calculator set to radians but you want degrees then anons answer is also correct. :)

acos(12/13)

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{12}}}{{\mathtt{13}}}}\right)} = {\mathtt{22.619\: \!864\: \!948\: \!04^{\circ}}}$$

I love maths too  !!   

No it is not just you.  The forum was down for over a week :)