Establish the identity.cos (x - y) - cos (x + y) = 2 sin x sin y
What will be an ideal response?
cos (x - y) - cos (x + y) = cos x cos y + sin x sin y - ( cos x cos y - sin x sin y) = 2 sin x sin y.
Mathematics
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Solve.2x + 5 = 3(x - 1)
A. -2 B. -8 C. 2 D. 8
Mathematics
Give an appropriate answer.Given the function f(x, y) and the positive number ? as in the formal definition of a limit, find a positive number ? as in the definition that insures 
< ?.f(x, y) = 
; ? = 0.06
What will be an ideal response?
Mathematics
Subtract.-145 - (-28 )
A. -117 B. 173 C. -173 D. 117
Mathematics
Simplify the expression. Assume that all variables represent non-negative real numbers.
+ 
A. (2x2 + 9)
B. 55x2 
C. (-7x2 + 9)
D. (11x2 + 9)
Mathematics