Answer:
To show others that he is interested in maths and science, not only in art.
Explanation:
Henri Émile Benoît Matisse was a French artist, known for both his use of colour and his fluid and original draughtsmanship. He was a draughtsman, printmaker, and sculptor, but is known primarily as a painter
Ellsworth Kelly (A)
All known artists in the question have worked with landscape portraits, including Frida Kahlo who mainly did self-portraits. Ellsworth Kelly is known for his minimalism works.