Question

find the exact value of each expression.

1. sin 50° cos 40° + sin 40° cos 50°
2. (tan pi/3 + tan pi/6) / (1- tan pi/3 tan pi/6)

Answer 1

1. sin (50+40)= sin 90

Answer 2

@babybaby baby can you do this ?

Answer 3

\[\sin(a + b) = \sin a\cos b + \sin b \cos a\]

Answer 4

@jasonxx i dont really understand the topic

Answer 5

Oh, it's Trigonometry.

Answer 6

it says use the expansion of sin (A+B)= sin A cos B+ cos A sin B where A= 50, B=40 clear baby?

Answer 7

ok

Answer 8

ill try it

Answer 9

cool :)

Answer 10

standard formula :
\(\huge tan (A+B)=\frac{tan A+tan B}{1-tanA\: tanB}\)
put A = pi/3, B = pi/6
\(\huge tan (\pi/3+\pi/6)=\frac{tan (\pi/3)+tan (\pi/6)}{1-tan(\pi/3)\: tan(\pi/6)}\)
so
\(\huge\frac{tan (\pi/3)+tan (\pi/6)}{1-tan(\pi/3)\: tan(\pi/6)}=tan(\pi/2)=\infty\)
did u get this ?

Answer 11

Sine of a Sum of Two Angles
------------
sin(α + β) = sinα cos β + cos α sin β.

= sin 50° cos 40° + sin 40° cos 50°
Decide which is alpha and which is beta, add, and take the sine of the sum.