Integrate cos x / (cos x/2 + sin x/3)^3 0 to pi/2

Ques 6 part i 

Elements of maths

indefinite integral6 

If D is the mid .point of side of side BC of a ΔABC, P and Q are two points lying respectively on the sides AB and BC such that DP is parallel to QA. Prove that ar(ΔCQP) = 1/2 ar(ΔABC).

• Area of elliptical shape who is a=5 and b=3.5 
  

4.2 8th problem solution is wrong its yz-zx

In 11th ncert book ,ex. 10.3 ,  3 q. That is y=0 what is the coeffocient of x and constant c

• A solid right circular cone of diameter 14 can and height 8 cm is melted to form a hollow sphere.If the external diameter of sphere is 10 cm then find it's internal diameter

Is it necessary to do reference books like Rd sharma for exams of class 9th? 

Write expression for energy stored in a spring

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