3 years ago

What is the correct answer for both ?

Mathematics

2 answers:

lakkis [162]3 years ago

4 0

Answer:

19. Option A

20. Option B

Step-by-step explanation:

yulyashka [42]3 years ago

4 0

Answer of 19 is A by using the a^2 - b^2 = ( a - b) ( a + b) so this will be (r-1 )( r+1) because we have r^2 so we have to factorize it

Answer of 20 is B by following the same steps

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Sketch the curve with the given vector equation. Indicate with an arrow the direction in which t increases. r(t) = 4 cos(t)i + 4

slega [8]

Answer:

The equation to this question is " $x^2+y^2=16$ "

Step-by-step explanation:

Given value:

$\to r(t) = 4 \cos (t)i + 4 sin(t)j + k\\where \\\\\to x(t)= 4 \cos t\\\to y(t) = 4 \sin t\\\to z(t)=1\\$

$\to x^2+y^2= 16 \cos^2 t +16 \sin^2 t\\\\\to x^2+y^2= 16 (\cos^2 t +\sin^2 t)\\\\\therefore (\cos^2 t +\sin^2 t =1)\\\\\to x^2+y^2= 16 (1)\\\\\to x^2+y^2= 16\\\\\to z=1$