Write the sum as a product And the value of the product 1 po

Write the sum as a product. And the value of the product. -1 points SPNCalc? 74408, Solve the given equation. (Enter your answers as a comma separated list. Let be any integer, Round terms to twe decimal places where appropriate -it points SPreCalc? of the given equation. (inter your answers as a comma separated list. Let k be any integer. Round terms to two decimal places where appropriate.) My Notes My Notes Asa Your Teacher

Solution

1) cos15x + cos6x

Use formula cosA +cosB = 2cos[(A+B)/2]*cos[(A - B)/2]

cos15x + cos6x = 2cos(15x+6x)/2cos(15x -6x)/2

= 2cos(21x/2)cos(9x/2)

2) 2sin37.5 sin97.5

use formula : 2sinAsinB = cos(A B) cos(A + B)

2sin37.5 sin97.5 = sin(-60) - cos(135)

= -sin60 - cos135

= -sqrt3/2 + 1/sqrt2

= [ -2sqrt(3) +1]/2sqrt(2)