PEMDAS (order of operations rules) require that we perform operations in a certain order: anything inside parentheses first, followed by any exponentiation, followed by mult. and div., finally followed by addition and subtraction.
Thus, we must evaluate 5+8÷4-1 first, as it's inside parentheses. Focusing on the division first, we get 5+8÷4-1 = 5 + 2 - 1, or 6.
Then we have 5 - [6], which comes out to -1.
3+(-4)=(-1)
so, 3 is the missing number
Answer:
3=1/5
Step-by-step explanation:
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Recall that 2sin(x) cos(x) is actually equal to sin(2x).
We can prove this by expanding sin(2x) to sin(x + x).
sin(x + x) = sin(x) cos(x) + cos(x) sin(x) = 2sinxcosx
Thus, 2sin(x/2)cos(x/2) can be rewritten in the form:
sin(2x/2), and this simplifies down to sinx.
