Cos 105cos 15 <br> what’s the answer to this

Evaluate 9+12÷3-1•4+2 using the correct order of operations

natita [175]

The answer is 11 if you use PEMDAS! Here is my work:
9+4-4+2 = I multiplied and divided first
13-4+2....9+2....11
Hope this helped :))

4 0

3 years ago

The diagram shows a parallelogram. work out the value of x

muminat

Answer:

x = 39

Step-by-step explanation:

The opposite angles of a parallelogram are congruent, so

3x - 15 = 2x + 24 ( subtract 2x from both sides )

x - 15 = 24 ( add 15 to both sides )

x = 39

3 0

2 years ago

I think I know the answer but just in case can someone help me ? And give me an explanation

RideAnS [48]

You multiply both sides by 9 first so you have -45=y-7. then add 7 to both sides to get y=-38

5 0

3 years ago

Assume z = x + iy, then find a complex number z satisfying the given equation. d. 2z8 – 2z4 + 1 = 0

kodGreya [7K]

Answer: complex equations has n number of solutions, been n the equation degree. In this case:

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i11,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i101,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i191,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i281,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i78,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i168,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i258,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i348,75°}$

Step-by-step explanation:

I start with a variable substitution:

$Z^{4} = X$

Then:

$2X^{2}-2X+1=0$

Solving the quadratic equation:

$X_{1} =\frac{2+\sqrt{4-4*2*1} }{2*2} \\X_{2} =\frac{2-\sqrt{4-4*2*1} }{2*2}$

$X=\left \{ {{0,5+0,5i} \atop {0,5-0,5i}} \right.$

Replacing for the original variable:

$Z=\sqrt[4]{0,5+0,5i}$

or $Z=\sqrt[4]{0,5-0,5i}$

Remembering that complex numbers can be written as:

$Z=a+ib=|Z|e^{ic}$

Using this:

$Z=\left \{ {{{\frac{\sqrt{2}}{2} e^{i45°} } \atop {{\frac{\sqrt{2}}{2} e^{i-45°} }} \right.$

Solving for the modulus and the angle:

$Z=\left \{ {{\sqrt[4]{\frac{\sqrt{2}}{2} e^{i45}} = \sqrt[4]{\frac{\sqrt{2}}{2} } \sqrt[4]{e^{i45}} } \atop {\sqrt[4]{\frac{\sqrt{2}}{2} e^{i-45}} = \sqrt[4]{\frac{\sqrt{2}}{2} } \sqrt[4]{e^{i-45}} }} \right.$

The possible angle respond to:

$RAng_{12...n} =\frac{Ang +360*(i-1)}{n}$

Been "RAng" the resultant angle, "Ang" the original angle, "n" the degree of the root and "i" a value between 1 and "n"

In this case n=4 with 2 different angles: Ang = 45º and Ang = 315º

Obtaining 8 different angles, therefore 8 different solutions.

3 0

2 years ago

Can someone help me with this question please.

galina1969 [7]

Answer:

6, 8, and 10.

Step-by-step explanation:

You could work this out with the pythagorean theorem, by proving that 6^2, 36, plus 8^2, 64, equals 100. The fastest way, however, is to use pythagorean triples. These are predetermined sets of numbers that work as side lengths for right triangles. The first two are 3, 4, and 5, which form a right triangle, and 6, 8, and 10, shown here.

5 0

2 years ago

Cos 105cos 15 what’s the answer to this