Question

What is the exact value of sin 75°?

6√−2√ / 4

6√+2√ / 4

2√−6√ / 4

−2√+6√ / 4

Answer 1

do u know

Answer 2

no i do not

Answer 3

well in class what method u use to get exact values?

Answer 4

its an online class, im getting ahead in math for high school for i don't have to take it my senior year, so I haven't learned this yet.

Answer 5

oh k

Answer 6

Use the identity: sin(A+B) = sin(A)cos(B) + sin(B)cos(A)

In this case 75 can be split up nicely as 30 + 45:

(working in degrees)

sin(70) = sin(30 + 45)
sin(30+45) = sin(30)cos(45) + sin(45)cos(30)

Answer 7

u know what identities are right?

Answer 8

yes

Answer 9

ohk u understand what i did so far

Answer 10

yeah

Answer 11

= sin(45) cos(30) + cos(45) sin(30)
\[(\frac{ 1 }{ \sqrt{2} })\times(\frac{ \sqrt{3} }{ 2 })+(\frac{ 1 }{ \sqrt{2}}\times \frac{ 1 }{ 2 })\]

Answer 12

Please see

Answer 13

Very much saying what ayeshaafzal221 is saying. He got it all correct. I just wanted to share the table.

Answer 14

\[\frac{ \sqrt{3} +1}{ 2\sqrt{2}}\]

Answer 15

Good job ayeshaafzal221

Answer 16

thank you guys

Answer 17

do u know hw to Rationalizing denominator?

Answer 18

a little bit but im not so good with them

Answer 19

√2(√3+1) / (2√2√2)

= (√6 + √2) / 4

Answer 20

sorry about late reply the equation wasnt coming up

Answer 21

do u understand now