Question

thanks

Answer 1

sin^2 = 1- cos ^2 ok?
replace and let the terms all in left hand side , the right hand side =0. Show me that step, please

Answer 2

Do you know how to solve quadratic ?

Answer 3

no.....

Answer 4

But we have no way to find out the solution without quadratic. How can I help??

Answer 5

a =pi

Answer 6

@cutegirl I shouldn't give you a free answer because it doesn't help you on long run.

Answer 7

got it

Answer 8

3cos a +3 = 1 - cos^2 a
cos^2a +3cosa +2=0
(cos a+2) (cos a +1) =0
cos a +2 never =0 , because it is out of range
hence , just cos a +1 =0 , then cos a =-1, hence a = pi + 2kpi.

Answer 9

yup. if limit is given, like from 0 to 2pi, then the answer is a =pi
if you don't have any limit, then a = pi +2kpi

Answer 10

thanks so much !!!!

Answer 11

I don't know, you must look at your problem (the paper) , it is not up to me.

Answer 12

ow i c thanks