Question

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Answer 1

Answer:

my dear the correct formula will be √A^2+B^2+2ABcos theta

as the A& B= a

so, we can write the formula as

2acos theta /2

now, if theta =0 ,than

2acos0/2

=2acos 0°

=2a

because cos0°=1

if theta =60°

2acos60/2

=2acos30°

=2a×√3/2

=√3a

if theta=90°

2acos90/2

=2acos45°

=2a×1/√2

=√2a

if theta=120

2acos120/2

=2acos60°

=2a×1/2

=a.

.

if theta= 180

=2acos180/2

=2acos90°

= 0

because cos90°= 0& if we multiply any number by 0 than the result will be 0

I hope you will understand

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Answer 2

Answer:

Hiiii,

2acos theta /2  

----------------------------------------------------------

now, if theta =0 ,than

2acos0/2

=2acos 0°

=2a  

because cos0°=1

-----------------------------------------------------------

if theta =60°

2acos60/2

=2acos30°

=2a×√3/2

=√3a

----------------------------------------------------------  

if theta=90°  

2acos90/2

=2acos45°  

=2a×1/√2  

=√2a

---------------------------------------------------------

if theta=120

2acos120/2

=2acos60°

=2a×1/2

=a.

-----------------------------------------------------------------

if theta= 180

=2acos180/2

=2acos90°

= 0

because cos90°= 0& if we multiply any number by 0 than the result will be 0  

#Hope it will help you

#mark me brainliest