Question

@callisto, Help! How do i find the exact value of:

tan(135°) + sin(30°) cot (120°):

Answer 1

scientific caclulator. then do proecesses to decimals

Answer 2

put value for sin 30 and take cot as cot(60+60)

Answer 3

tan(135°) = -tan 45 =-1
sin(30°) =1/2
cot (120°) = 1/tan120 = 1/ -tan60 = 1/-sqrt 3

Can you work this out?

Answer 4

k, one sec

Answer 5

tan is added with the other values, is sin multiplied by cot?

Answer 6

haizzz wouldn't it be nice to be personally tagged in a question *sigh* haha

Answer 7

yes

Answer 8

@Open2study

Answer 9

yes?

Answer 10

am i solving by decimal approximation?

Answer 11

Hmmm...
tan(135°) + sin(30°) cot (120°):
= -tan(180 - 135) + sin30 (-cot (180-120))
= -tan45 + sin30 (-cot60)
= -1 + (1/2)(-1/tan60)
= -1 + (1/2) (-1/sqrt3)
Understand it? and can you try to simplify the answer?

Answer 12

Is it sqrt (3)/2 - 1?

Answer 13

Not really... Can you try again??

Answer 14

If its in decimals, is the answer -0.1339?

Answer 15

Nope...

Answer 16

Is it 1/2 (√3 - 2)?

Answer 17

Just a minute!

Answer 18

ok

Answer 19

Finally, I decided not to trust my calculator :S

Answer 20

Omg, You went through so much trouble scanning and all just to help me! Thank you so much Jos!

Answer 21

You're welcome.....

Answer 22

one question, Hoe did it go from -2√3 - 1 / 2√3 to -2√3 (√3) -√3 / 2(3)?

Answer 23

so the exact value is -6 √-3 / 6

Answer 24

I think so... and I hope so....

Answer 25

Wow. Thank you so much again @Callisto! You have helped me so much!

Answer 26

Welcome :)

Answer 27

@callisto, Im finding the exact value of sin (30)

Answer 28

isnt it sin(60) = sqrt(3)/2?

Answer 29

it lies on quadrant I, positive

Answer 30

yess

Answer 31

How come in your answer its 1/2?

Answer 32

sin(60) = sqrt(3)/2 <- correct
BUT
sin 30 = 1/2 ....

Answer 33

Ohhh. ok, nvm I was concentrating too much on one thing. So sorry to bother you again

Answer 34

That's not bothering :P

Answer 35

Thank you for the clarification. I get lost many times, and some times for no reason :P

Answer 36

Can you get it now?

Answer 37

@callisto, sorry! this is the last time I will call for your assistance today, I am going to be now. I am just double checking before submitting. How come in the procedure, you are constantly adding sqrt (3), the ones written in red?

Answer 38

Do the rationalisation

Answer 39

my teacher said it's not good to leave a sqrt in the denominator, so it's my practice to do the rationalisation

Answer 40

Oh! Thats right! Im sorry, Im just really sleepy so Im not thinking straight. Thank you so much Callisto! I have to go to bed no:) Thank you!

Answer 41

welcome ! Good night :)