Answer:
Step-by-step explanation:
cos (A+B) + sin (A-B) = 2 sin (45°+A) cos (45° + B)
= 2 (sin45°cosA + cos45°sinA)(cos45°cosB - sin45°sinB)
But sin45=cos45 =(sqrt2)/2
= 2 ((sqrt2)/2 *cosA + (sqrt2)/2 *sinA)((sqrt2)/2 *cosB -(sqrt2)/2 *sinB)
= 2 ((sqrt2)/2 *(cosA + sinA))*((sqrt2)/2 *(cosB - sinB))
= 2*(sqrt2)/2 * (sqrt2)/2 * (cosA + sinA)*(cosB - sinB)
= (cosA + sinA)*(cosB - sinB)
= cosAcosB +sinAcosB -cosAsinB - sinAsinB
Regrouping:
= (cosAcosB- sinAsinB) + (sinAcosB -cosAsinB)
= cos (A+B) + sin (A-B)
Answer:
sure why not
Step-by-step explanation:
Answer: 118 degrees
Step-by-step explanation:
Angles in a triangle add up to 180 degrees.
So...
180 - (42+20) = 118 degrees
Answer:
Step-by-step explanation:
52 =2 , 4 , 13 , 26
36 = 2 , 3 , 4 , 6 , 9, 12 , 18
57 = 1 , 57
63 = 3 , 7 , 9 , 21
96 = 2 , 3 , 4 , 6, 8, 12, 16 , 24 , 32 , 48