Math, asked by madhu985, 1 year ago

sin(x+y)sin(x-y)=sin²x-sin²y=cos²y-cos²x​

Answers

Answered by mayank1044
3

Answer:

first of all use the sum identity then change the sin into cos and cos into sin as you can see

similarly you can prove for

Attachments:
Answered by TanikaWaddle
2

Given : \sin (x+y)\sin (x-y)= \cos^2y - \cos^2x

Step-by-step explanation:

\sin (x+y)\sin (x-y)= \cos^2y - \cos^2x\\\\\text{solving LHS}\\\\\sin (x+y)\sin (x-y)\\\\(\sin x \cos y+\cos x \sin y)(\sin x \cos y-\cos x \sin y)\\\\(a+b)(a-b) = a^2-b^2\\\\\sin^2 x+ \cos^2y-\cos^2x\sin^2y\\\\(1-\cos^2x)\cos^2y- \cos^2x(1-\cos^2y)\\\\\cos^2y-\cos^2ycos^2x-cos^2x+cos^2xcos^2y\\\\\cos^2y-\cos^2x

hence proved

#Learn more :

https://brainly.in/question/10780881

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