Question

complete explanation of cos45cos60-sin45sin60

Answer 1

this is identical to cos(45 + 60)

Answer 2

compound angle identity

cos (A + B) = cosAcosB - sinAsinB

Answer 3

how to evaluate this quistion

Answer 4

ok - its = cos 105 degrees
using my calculator this = -0.2588

Answer 5

need any more help?

Answer 6

cos45=1/sqrt2and cos60=1/2so i am putting their values
(1/sqrt2*1/2-1/sqrt2*sqrt3/2)
i have problem in their multiplication

Answer 7

in next step it will be 1/2sqrt2 *sqrt3/2sqrt2 now explain how to take LCM in this case please

Answer 8

1/2sqrt2 - sqrt3/2sqrt2 = sqrt3/4

Answer 9

sorry the last part is wrong its (1 - sqrt3) / 2sqrt2

Answer 10

-this checks out ok against - 0.2588 which i quoted earlier

Answer 11

but if you solve it on calculator its showing -sqrt6+sqrt2/2

Answer 12

no - there an error somewhere -sqrt6 + sqrt2/2 = -1.7424

Answer 13

so explain me how you take LCM 2sqrt2 it can be 8