Hi, a recipe calls for 1/2 cups of flour. How much flour should be used if only half of the recipe is to be made. Thank You.
2 answers:
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Answer:
Step-by-step explanation:
Using the addition formulae for cosine
cos(x ± y) = cosxcosy ∓ sinxsiny
---------------------------------------------------------------
cos(120 + x) = cos120cosx - sin120sinx
= - cos60cosx - sin60sinx
= - cosx -
sinx
squaring to obtain cos² (120 + x)
= cos²x +
sinxcosx +
sin²x
--------------------------------------------------------------------
cos(120 - x) = cos120cosx + sin120sinx
= -cos60cosx + sin60sinx
= - cosx +
sinx
squaring to obtain cos²(120 - x)
= cos²x -
sinxcosx +
sin²x
--------------------------------------------------------------------------
Putting it all together
cos²x + cos²x +
sinxcosx +
sin²x +
cos²x -
sinxcosx +
sin²x
= cos²x + cos²x +
sin²x
= cos²x +
sin²x
= (cos²x + sin²x) =
Answer:
(- 3, 37) and (- ,
)
Step-by-step explanation:
Given the 2 equations
2x² - y + 19 = 0 → (1)
y + 11x = 4 → (2) ← subtract 11x from both sides
y = 4 - 11x → (3)
Substitute y = 4 - 11x into (1)
2x² - (4 - 11x) + 19 = 0
2x² - 4 + 11x + 19 = 0
2x² + 11x + 15 = 0 ← in standard form
(2x + 5)(x + 3) = 0 ← in factored form
Equate each factor to zero and solve for x
2x + 5 = 0 ⇒ 2x = - 5 ⇒ x = -
x + 3 = 0 ⇒ x = - 3
Substitute these values into (3) for corresponding values of y
x = - : y = 4 +
=
⇒ (-
,
)
x = - 3 : y = 4 + 33 = 37 ⇒ (- 3, 37 )