Question

what is the exact solution of cos (17pi/6)?

Answer 1

so what is pi/6 radians in degrees?

Answer 2

30

Answer 3

yes. and 17 x 30 = 510.

so u know that 510 = 360 + 150 and tht at every 360 degrees cos 360 equals cos 0 ?

Answer 4

yes

Answer 5

which actually leaves you with cos of 150.

and cos 150 is nothing but cos(180-150) = cos 30.

cos 30 is root of 3/2, however 150 is in quadrant 2, so cos will be negative.

ans should be - root of 3/2

Answer 6

Thank you!

Answer 7

i want to verify something....

Answer 8

is csc (-17pi/6) = 2?

Answer 9

is that right?

Answer 10

I think its - cosec(17 pi/6) ,

which is actually - cosec 150

cosec is in 2nd quadrant where sin and cosec both are POSITIVE.

So cosec 150 = cosec 30 = 2.

cosec 150 will remain 2 since in quad 2 its positive so ans should be -2.

Answer 11

oh okay. I get it now. Thank you!