Question

Express as the sum or difference of two trigonometric ratios
sin(theta + 75)sin(theta + 15)
@ganeshie8

Answer 1

@ikram002p

Answer 2

Lookup 2sinAsinB formula

Answer 3

lol
i dint get it yet

Answer 4

@ganeshie8

Answer 5

http://www.mash.dept.shef.ac.uk/Resources/4_4trigidentities.pdf

Answer 6

\[\large 2 \sin A \sin B = \cos(A-B) - \cos (A+B)\]

Answer 7

\[\large \sin(\theta + 75)\sin(\theta + 15) = \dfrac{1}{2}*2 \sin(\theta + 75)\sin(\theta + 15) \\ \ \\\large = ? \]

Answer 8

Notice that
\(A = \theta + 75\)
\(B = \theta + 15\)

Answer 9

\[\large \dfrac{1}{2}*2 \sin(\theta + 75)\sin(\theta + 15) = ? \]

Answer 10

\(A - B = 60\)

\(A + B = 2\theta + 90\)

Answer 11

\[\large \dfrac{1}{2}*2 \sin(\theta + 75)\sin(\theta + 15) = \dfrac{1}{2}\left[\cos (60) - \cos (2\theta + 90)\right] \]

Answer 12

see if that looks okay so far