Math, asked by kaaraksh, 9 months ago

cos(A+B)=0, sin(A-B)=?

Answers

Answered by Anonymous
25

AnswEr :

Given that,

 \sf \: cos(A + B) = 0

We have to find the value of sin(A - B)

Here,

 \sf \: cos(A + B) = 0 \\  \\  \longrightarrow \:  \sf cos(A + B) = cos90 \\  \\  \longrightarrow \:  \sf \ \: A + B  = 90^{\circ} \\  \\  \longrightarrow \boxed{\sf B = 90  - A }

Now,

 \sf \: sin(A - B) \\  \\  \dashrightarrow \:  \sf \: sin \bigg(A - (90 -  A )\bigg) \\  \\  \dashrightarrow \sf \: sin(2A - 90) \\  \\  \dashrightarrow \: \sf \: sin2Acos90 - sin90cos2A \\  \\  \dashrightarrow \:  \sf \:  - cos2A \:

Thus,sin(A - B) = - cos2A

NoTE

  • sin(A + B) = sinAcosB + cosAsinB

  • sin(A - B) = sinAcosB - cosAsinB

  • cos(A + B) = cosAcosB - sinAsinB

  • cos(A - B) = cosAcosB + sinAsinB
Answered by MarshmellowGirl
28

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