solve both questions........
if you don't know leave this
with explanation ✔️
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Step-by-step explanation:
4.(cosx-cosy)²+(sinx-siny)²
={-2sin(x+y/2)sin(x-y/2)}²+ {2cos(x+y/2)sin(x-y/2)}
=4sin²(x+y/2)sin²(x-y/2)+4cos²(x+y/2). sin²(x-y/2)
=4sin²(x-y/2){sin²(x+y/2)+cos²(x+y/2)}
=4sin²(x-y/2) [sin²A+cos²A=1]
5. (sin7x+sinx)+(sin5x+sin3x)
=2sin4xcos3x+2sun4xcosx
=2sin4x(cos3x+cosx)
=2sin4x(2cos2xcosx)
=4cosx.cos2x.sin4x
hey, do you read in class XI ?.
this is the qsn. of class XI mathematics book
If you are XI standard plz. tell me
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