Question

Prove it
step by step
urgent!



No unnecessary answer
​

Answer 1

Answer:

Step-by-step explanation:

use the formula cos(a+b)-cos(a-b)=-2sinasinb

cos(a+b)=cosacosb-sinasinb

cos(a-b)=cosacosb+sinasinb

from this two formulas we arrived the formula cos(a-b)-cos(a+b)

acc to question

a=3π/4

b=x

substitute this two values cos(a+b)-cos(a-b)=-2sinasinb

=-2sin3π/4.sinx

=-2.1/√2.sinx [ sin3π/4=1/√2]

=-√2sinx

hence proved

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