Question

write the expression as the sine, cosine, or tangent of an angle: cos60°cos10°-sin60°sin10°

Answer 1

@jim_thompson5910

Answer 2

use the identity

cos(x+y) = cos(x)cos(y) - sin(x)sin(y)

Answer 3

could you do it for me?

Answer 4

@jim_thompson5910

Answer 5

compare

cos60°cos10°-sin60°sin10°

to

cos(x+y) = cos(x)cos(y) - sin(x)sin(y)

Answer 6

what is x? what is y?

Answer 7

10 and 60?

Answer 8

actually 60 and 10, but you got the idea

cos(x+y) = cos(x)cos(y) - sin(x)sin(y)

cos(60+10) = cos(60)cos(10) - sin(60)sin(10)

cos(70) = cos(60)cos(10) - sin(60)sin(10)

Answer 9

that's all?

Answer 10

yep

Answer 11

what about sin110°cos80°+cos110°sin80°

Answer 12

@jim_thompson5910

Answer 13

use

sin(x+y) = sin(x)cos(y) + cos(x)sin(y)

Answer 14

ok and whats the formula foe tan325-tan86/1+tan325tan86

Answer 15

have a look at this page

http://www.sosmath.com/trig/Trig5/trig5/trig5.html

Answer 16

there are some useful trig identities you'll need

Answer 17

thank you so much

Answer 18

yw

Answer 19

i do not see the tan formula

Answer 20

@jim_thompson5910

Answer 21

look for tan(u+v)

Answer 22

ok i see