Question

use the trigonometric function vngles given in this section to evaluate each experssixpression such as cot"2 90° means (cot90°)"2 , which is equal to 0"2 = 0.

sec"2 180° -35in"2 360° +cos180°

Answer 1

what? I don't understand...
do you mean
\[\sec^2(180^o)-3 \sin^2(360^o)+\cos(180^o)\]?

Answer 2

Yes :)

Answer 3

do you know how to evaluate cos(180)?

Answer 4

yes it is -1... according of what my teacher said..

Answer 5

\[\sec^2(180)-3 \sin^2(360)+\cos(180) \\ \frac{1}{(\cos(180))^2}-3(\sin(360))^2+\cos(180)\]

Answer 6

all you really need to do for this question is know how to evaluate cos(180) and sin(360)
the rest his order of operations

Answer 7

but why do you convert sec to cos? and what do I do with the 2's?

Answer 8

sec(x)=1/cos(x)

Answer 9

cos and sec are reciprocal functions of one another

Answer 10

can you tell me what cos(180) and sin(360) equals?

Answer 11

cos= -1 and sin =0

Answer 12

so we are just going to replace those items real quick like this:
\[\sec^2(180)-3 \sin^2(360)+\cos(180) \\ \frac{1}{(\cos(180))^2}-3(\sin(360))^2+\cos(180) \\ \frac{1}{(-1)^2}-3(0)^2+-1 \]

Answer 13

now just apply order of operations

Answer 14

all equal -3?

Answer 15

1-3(0)-1 isn't -3

Answer 16

0?

Answer 17

seems great me
so if cos(180)=-1
then squaring both sides gives you (cos(180))^2=(-1)^2=1
and if sin(360)=0
then squaring both sides gives you (sin(360))^2=(0)^2=0
so yes we have 1-3(0)-1=1-0-1=1-1=0

Answer 18

Ya ! Thank you so much for heping me @freckles have a nice day ;)