Question

please answer this 116 and 117 with simple explanation.

Answer 1

Hey there !!!!!

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=(sin47/cos43)²+(cos43/sin47)²-4cos²45

We know that sin(90-Ф)=cosФ

So,

sin47=sin(90-43)=cos43

Now,

=(sin47/cos43)²+(cos43/sin47)²-4cos²45

=(cos43/cos43)²+(cos43/cos43)²-4cos²45

=1+1-4(1/√2)²

=2-4/2

=2-2=0

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117)  a²+b²+c²=ab+bc=ca---Equation 1

Multiplying equation 1 with 2 on both sides

 2(a²+b²+c²)=2(ab+bc+ca)

a²+a²+b²+b²+c²+c²=2ab+2bc+2ca

a²-2ab+b²+ a²-2ac+c²+b²-2bc+c²=0

(a-b)²+(a-c)²+(b-c)²=0

Sum of squares cannot be zero

⇒⇒(a-b)=0 (b-c)=0 c-a=0

a=b   b=c  c=a

So,

a=b=c

Now, a+c/b= a+a/a=2a/a=2

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Hope this helped you......................